A "Keep Out" sign posted on a fence
PHOTO: Sandy Millar on Unsplash

Online advertising is hard to escape. Social media platforms, games, news sites and search engines rely on advertising to generate revenue.

As of 2021, the global online advertising industry was worth more than $186 billion, according to IMARC, and is set to expand further at a compound annual growth rate of 10.9%.

Unobtrusive advertising can be effective without marring the end user's experience, but large, distracting images, pop-ups and other invasive tactics are driving users to employ ad blocking tools.

What Is Ad Blocking?

Ad blocking refers to hiding ads that appear in your web browser (or other web-connected apps).

Ad blockers range from simple tools that prevent browsers from opening pop-up windows or running certain scripts to more sophisticated extensions and applications that block all content from known advertisers.

Some ad blockers go a step further and also block tracking links. If a user clicks on a link with tracking information that’s linked to a known advertising company, the extension will ask the user if they still want to continue.

How Do Ad Blockers Work?

Ad blockers fall into a few different categories:

  • Browser extensions
  • Standalone desktop apps
  • Mobile apps
  • More sophisticated systems

These options all attempt to achieve the same goal: giving the user an ad-free experience. They use filter lists, or block lists, to identify undesirable content.

The ad blocker looks at each request the browser wants to send out and checks whether it's in the block list. If it is, it stops the request. Depending on how the tool is set up, it may show something else — like a picture — in place of the ad. Or the space might appear blank.

Browser extensions, like AdBlock, are the most popular type of ad blocker. These extensions block content shown on web pages but nothing else. Other ad blockers are more powerful and work in multiple applications, such as music and game apps. These systems work either at the operating system level or by reading all traffic on the network.

One positive side effect of modern ad blockers is that they block the request for the ad, rather than allowing the browser to download the ad and then decide not to display it. An ad blocker can save those on metered internet connections a significant amount of data, and make web pages load faster.

Related Article: How Blockchain Is Changing Advertising

Filters and Whitelists

Some ad blocking companies have opted-in to voluntary programs that allow advertisers to bypass blocking scripts.

There are currently two major programs:

These programs set standards —- such as size and placement of ads, what types of animations are allowed, rules for using sound and video — advertisers must comply with to have their ads included on a whitelist.

The Coalition for Better Ads homepage said its standards “identify the ad experiences that fall beneath a threshold of consumer acceptability and are most likely to drive consumers to install ad blockers.”

According to the Coalition, more than 150,000 consumers participated in the research and development of their standards.

Similarly, Acceptable Ads solicits user feedback before including advertisements in its whitelists. Inclusion is free for smaller advertisers, but larger media organizations must pay a fee for consideration.

Is Ad Blocking Safe to Do?

Blocking online advertisements using well-known, reputable tools, such as Adblock Plus or uBlock Origin, is safe. These browser extensions don't read personal data. They simply look at a website's code and compare any requests for information from external sources with their own block lists. Using this kind of ad blocker won't put the user at risk.

Ad blocking software is something ad companies and publishers have tried, and so far failed, to fight against. German media giant Axel Springer attempted to sue Eyeo, the company that runs Adblock Plus, for copyright infringement.

Axel Springer first raised the case in 2015, arguing against the use of ad blocking tools and contesting the Acceptable Ads whitelisting service.

Initially, the courts ruled in Eyeo's favor, ruling that the "Adblock Plus browser extension does not breach laws on competition, copyright or market dominance."

Axel Springer appealed this ruling, however, and in 2016, the German courts ruled that Eyeo couldn't charge Axel Springer a fee to appear on its Acceptable Ads whitelist. However, the appeals court upheld the ruling that ad blocking services are legal.

The media company then went back to court with a new approach, claiming these services "change the programming code of websites."

Eyeo contested this code-changing claim, stating that ad blockers work on content that has already been delivered to the browser. In January 2022, a Hamburg court ruled in Eyeo's favor.

The court stated that, since Adblock Plus does not change how code is displayed on a user's device, it's not infringing copyright.

The ruling can be appealed in the European courts, and there have been other cases of companies taking ad blocking providers to court in the United States. However, for now, the courts consider ad blocking software to be legal.

The Best Ad Blockers for Web Browsers

Users of mainstream desktop browsers, such as Firefox and Chrome, have many options regarding ad blocking software. Some of the most popular ones are listed below.

1. uBlock Origin

Price: Free

Best for: Easy customization

uBlock Origin is a free ad blocking browser extension that offers support for both Firefox and Chrome. It's lightweight and offers good performance, even on less powerful hardware.

The extension is open source, allowing users to create and share their filter lists. They can also whitelist ads and have granular control over how the extension works, including enabling or disabling features on a per-website basis.

In addition to filtering ads, uBlock Origin is a script blocker and users can configure it to disable certain page elements. Blocking a page element isn't as efficient as blocking an ad, since the browser must download the content first, but this feature can still be helpful in hiding annoying content on websites.

The one downside of uBlock Origin is that it's only available as a browser extension. There's no desktop version, so it can't block ads in other internet-connected applications.

2. AdBlock

Price: Free

Best for: Multiplatform ad blocking

AdBlock is one of the oldest extensions and is still a trusted brand. It offers ad blocking features for Chrome, Firefox, Edge and Safari. The extension is available for desktop browsers, and there's also an iOS and Android version.

This tool relies on filter lists delivered by the developers. Users can add their own filter lists and whitelist websites. AdBlock is part of the Acceptable Ads program, which means advertisements that meet certain standards can bypass the blocker.

It's possible to turn off the Acceptable Ads feature, but the option to do so isn't made obvious.

3. Adblock Plus

Price: Free

Best for: User-friendly features

Despite having similar names, AdBlock and Adblock Plus are separate companies. Adblock Plus works similarly to AdBlock and offers extensions for Firefox, Chrome, Safari and Opera.

The developers have opted-in to the Acceptable Ads program, so advertisers can get their ads through the blocker if they're deemed unobtrusive. Bypassing the filter lists is free for small organizations, but larger brands must pay a fee.

Adblock Plus stands out because it's easy to use and gives plenty of feedback to its users. For example, it shows a counter that lets users see how many ads it has blocked on a page, giving reassurance that it's working.

The Acceptable Ads feature can be disabled, and users can customize the filter lists or whitelist individual websites.

Related Article: Using Google Local Service Ads? Why Not?

The Best Ad Blockers for Desktop

Ad blockers for web browsers can be very useful . But they don’t help with ads that appear outside of your browser.

The following desktop apps run in the background on a computer and can block ads in multiple applications.

1. AdLock

Price: $22/year on Windows, $11/year on Android

Best for: Blocking ads in games and apps

AdLock offers ad blocking solutions for Windows and Android. The app runs in the background and attempts to block traditional ads, as well as auto-playing video content, pop-ups and potentially dangerous websites.

The app blocks content before it's loaded, so it could reduce data consumption and speed up website loading times. Because it's a separate application that attempts to filter all web traffic, it can block ads in many downloadable games and apps, such as Skype.

However, AdLock does have some drawbacks. Some technical knowledge is required to set up the mobile version, and it isn't available on the Google Play Store, so users will need to sideload it.

2. AdGuard

Price: $79.99 once or $2.49/month

Best for: Malware blocking and parental controls

AdGuard is an all-in-one ad and malware blocking tool. It doesn't just block pop-ups and in-page advertisements. It also aims to block web trackers, malware and malicious websites.

The app protects users from phishing websites and malicious downloads. Users can also block other categories of websites, making the software useful as a parental control tool. In addition to the ad blocking app, there's a separate VPN application for users who want extra privacy online.

The application, which has been around since 2009 and gets regular updates, offers the option of a monthly subscription or a one-off lifetime fee.

The Best Ad Blockers for Mobile Devices

While some ad blocking tools above have mobile versions, they're primarily for desktop use. The following ad blocking software was designed with mobile users in mind.

1. 1Blocker X

Price: Free with in-app purchases

Best for: iOS ad blocking (Safari)

1Blocker X is an ad blocker for iOS devices and can be found in the iOS app store. It works with the Safari content blocker API to provide a streamlined, smooth experience, reducing mobile data usage and speeding up page loading.

The app is shipped with more than 115,000 content-blocking rules, offers regional ad blocking settings and allows users to customize the filters to their preferences. It's a surprisingly powerful tool for one that runs on a mobile device.

1BlockerX is free to download, and the unpaid version works quite well. Some features are behind a paywall, but the app doesn't use invasive tactics to get people to spend money.

2. Firefox Focus

Price: Free

Best for: Lightweight, privacy-focused browsing

Firefox Focus is an implementation of the Firefox browser available on iOS and Android. Users can install it via their respective app stores.

The browser has built-in anti-tracking and ad blocking features, as well as some privacy-focused settings like automatic cookie deletion and history clearing.

Users have a lot of control over settings and can tell the browser to block analytics, social trackers and advertisements. They can also set a custom search engine and activate “stealth” mode with a simple toggle.

It's possible to achieve most of these things with other browsers, but doing so requires some technical knowledge. Firefox Focus makes these options easier to find and offers a relatively privacy-respecting browsing experience out-of-the-box.

3. AdClear/AdClear Plus

Price: Free

Best for: Blocking ads in apps

AdClear is an Android ad blocking tool, and AdClear Plus is the iOS version. These apps go a step further than browser-focused ad blockers. They change the DNS settings on the phone or tablet and reroute web traffic through a VPN that filters out ads.

This means AdClear can block advertisements on both web pages and apps. The developers claim this can save bandwidth, reduce battery consumption and make apps run more quickly.

User reviews give mixed feedback on how effective the software is, but those who find in-app advertising frustrating may want to try AdClear to see how well it works with their setup.

Related Article: An Exploration of the Different Types of Digital Marketing

Advanced Ad Blocking Techniques

The ad blockers above work on one device at a time. Households or businesses with multiple computers, phones and tablets may find it time-consuming to keep all of those devices up-to-date.

One helpful option, especially for desktops and other devices that rarely leave the home network, is to set up an ad blocking proxy that all the devices connect to. One common option for this is Pi-hole.

Ad Blocking With a Raspberry Pi

Pi-hole is a network-wide ad blocking proxy designed to run on the Raspberry Pi, an affordable, compact computer.

While the system was created with the Raspberry Pi in mind, users don’t need to own one. The proxy software should work on any computer capable of running a relatively modern version of Ubuntu, Debian or a similar flavor of Linux.

How to Install Pi-hole

To install Pi-hole, simply set up a Raspberry Pi or another Linux computer with at least 512MB of RAM. Open a terminal on that computer, and use the following commands to clone the git repository for Pi-hole and install it.

sudo apt install git

git clone --depth 1 https://github.com/pi-hole/pi-hole.git Pi-hole

cd "Pi-hole/automated install/"

sudo basic-install.sh

Follow the on-screen installer prompts. The default options should be suitable for most users, so there's no need to change them unless you're a technical user and want to customize the installation.

The final screen of the setup will say "Installation Compete." Make a note of the IPv4 (or IPv6, if applicable) address listed on this screen. Next, log in to your router’s admin panel, and set the primary and secondary DNS to the IP address listed above.

Once this is done, any devices connecting to the router will use the Pi-hole for their DNS queries, assuming the device isn’t set to override the router and use other services.

What Does Pi-hole Do?

Pi-hole blocks ads at the DNS level. It has an extensive block list of known advertising addresses, and when a computer on the network attempts to load content from one of those addresses, it will block it.

Using Pi-hole instead of running blockers on each computer has several benefits:

  • There's no need to update blocking software on multiple machines
  • Pi-hole is open source and has large and regularly updated block lists
  • There's no subscription fee to pay
  • Instead of running bloated software on each device, the blocker is running on dedicated hardware
  • Pi-hole may also have privacy benefits (since you can use different DNS servers with it)

One downside Pi-hole is that it only works when the user’s device is connected to the same network the proxy is on. Therefore, if you have a computer or phone you regularly use on public Wi-Fi or through mobile data, you may still need another ad blocker.

Support Your Favorite Websites

Websites overloaded with intrusive advertising can be frustrating to use. But with internet ad spend expected to increase by more than 11% in 2022 (Statista), these annoyances aren’t going away anytime soon.

Many websites attempt to detect whether a user has an ad blocking tool installed. These websites often ask the user to disable the software — or whitelist the website — to continue providing support.

It might be worth whitelisting your favorite websites — the ones that offer high-quality content and don’t use intrusive advertising. Alternatively, consider donating to those websites through a Patreon or premium membership.

Creating content takes time, and hosting a website costs money. Supporting high-quality websites helps them continue to create useful content in the future.