What is Ad blocking?
Ad blocking is no technology or functionality it’s just about blocking of ads by the user if he is not interested to see any ad when he or she visits to any website. To understand ad blocking functionality let’s know the product called adblock plus which helps user block ads for them.
Interestingly Ad blockers can also go at a level of hardware and can block the ads at router level. It can plug into the internet router and can help blocking ads for all the IP’s passing via the same. This method is generally used by companies who wants to block ads are basically want to apply filter at company level
What is AdBlock Plus?
AdBlock plus is built using Gecko technology which is a web browser engine developed by Mozilla Foundation. Gecko works on a concept of ‘Content Policies’ which is a JavaScript or C++ object that is called whenever browser is requested to load something (e.g. website loading). Content policy is a code which plays a role in allowing what to be loaded and what not, there are multiple content policies with different definitions e.g. it could include no image loading for a site, different content as per browser, etc.
AdBlock has no default functionality and it does not block until unless the user ask for it. AdBlock is a functionality which is completely dependent on filters and these filters are nothing but set of rules that directs the adblock to work on or basically block that user is not interested to see, like ads on website. Using these filters you can also block malware, third party tracking’s, etc. To lot of it may feel that adding extension to the browser plays the role in blocking but the fact is the extension only gives the direction, it’s the same Gecko (web engine) technology which plays the role in blocking. The blocking ads are not that tough to do as it is well known that ads rendered from a different server and not the same from where the content is deployed thus making it easy to identify tags and advertising code in the page which is removed before the call is made to the ad server.
The default filters that are applied for default are:
- An ad-blocking list selected based on your language (EasyList)
- The Acceptable Ads list
NOTE: These default list can also be removed if not interested
Simple Working via image:
Step 1:
User opens any website on his browser, as soon as the request goes to the servers for content and ad, simultaneously adblock addon or extension which is installed in your browser comes in action too.
Step 2:
Adblock does all the processing, blocking as per the filters applied
Step 3:
Adblock blocks all the ads to appear on the website and the website is seen as per below image. The ad spot layout can also be changed showing user as if there was no ad spot available, but for that CSS and condition coding has to be done.
Adding to above three steps, there are multiple processing done, like ad server call, web server call, browser processing, etc. But in summary below image gives you the idea what action does ad blockers does.
How AdBlock plus blocks ads?
Three main functionality adblock uses are:
- Request blocking – This ensures to block the HTTP request which will prevent from loading thus saving in unnecessary requests and responses. This makes the page load faster, it includes:
- Blocking of known domain and sub domain from loading ads e.g. atdmt, ad, etc.
- Blocking of servers which associates with advertisements. It could be any cdn, or google creative server or any third party server also
- Blocking of known scripts which help in loading ads
- Generally all kind of iframes are checked before rendering on the page as iframe is well known for serving ads
- Element hiding – This feature works by injecting CSS code in the website which then helps in hiding the elements that are requested to be blocked, using this the ads are completely removed from the page, but will only help hiding ads but not stopping them to load ads which will take its own time in the first place thus this slows down in loading the page.
- Creative (Image) Blocking – Adblock just not block as per domain or sub domain but also as per image dimensions, common IAB ad sizes like 728×90, 300×250, 160×600, 120×600, 468×60, etc. are blocked no matter they are ads are not. This is done as these sizes are generally ad units placed on websites. You can make use of filter to keep this option on or off. To check this, please visit to the link : Click Here where image samples are shown for ads. Now on off adblock to see what happens.
Combination of both are the filters which are then applied by the user to block ads according to their request and requirement