What Happens When You Click On An Ad? [Infographic]

When you click on an ad, it’s not just the advertiser and the website hosting the ad who find out about it. To help them improve the performance of ads in general, there are at least eight different types of companies potentially monitoring every ad click on the internet.

Here are the stages of tracking that you can expect almost any time you click on an ad on the internet.


What Happens When You Click On An Ad?


Stage 1: Website Tracking

Unless the website you click the ad on has a direct relationship with its advertisers, they will likely only be told about clicks via the ad network or supply-side platform (SSP) they contract with (more on that in a moment). They may also occasionally have extra tracking technology in place that verifies clicks (but this is rare).

However, more and more websites are opting to have external link clicks tracked via their analytics, and this could potentially include any ads running on their site. This is generally done via something like Google Tag Manager, as it’s easy to set up, and then the stats are collected in Google Analytics.

For most websites, their Google Analytics data is held on Google’s servers. Google Analytics data should not be shared with Google unless specific options are ticked within its setup.


Stage 2: Ad Networks, Supply Side Platforms, & Ad Servers

Advertisers almost always have a whole array of tracking that fires when an ad is clicked on. This is because websites generally don’t have direct relationships with the advertisers who place ads on their sites.

Selling ad space is a difficult and somewhat tedious job, so most websites outsource it to an ad network or SSP (such as Google AdSense, Media.net, or Monumetric).


The theoretical difference between an ad network and SSP is that ad networks manage ads for you while an SSP is a platform you manage yourself.

In reality, however, most Supply Side Platforms offer enough automated tools that the end result is pretty indistinguishable.


Ad Networks and SSPs run thousands of ads across thousands of websites, and to make sure that everyone (including them) makes as much money as possible, they run ads where they are most likely to get clicked on.

To do this, they need to be able to find out when ads get clicked on, so they will have click tracking built into their ad code (which will be run via an ad server – something like Google Ad Manager).

The ad server will also get access to this click data. As well as aggregating this data for their own ends (such as marketing their services), making sure click tracking is working is a large part of what they are being paid for, so they do actually need to be able to see click data.


Stage 3: Ad Agencies, Demand Side Platforms, & 3rd Party Ad Servers

Just like websites, ad networks and SSPs generally do not have (many) direct relationships with advertisers but instead, go through ad agencies or Demand Side Platforms (DSPs).

Ad Agencies are responsible to advertisers for performance, so they will generally track clicks themselves to ensure they can move budget between ad networks to get the best performance. Their ad code will be run through something like Google Campaign Manager.


Demand Side Platforms

Ad Agencies work on behalf of advertisers to place ads in the right places, and will generally work with multiple ad networks to achieve this. To manage this, they will likely use a DSP, which is like a marketplace for ad inventory. Many ad networks and SSPs sell ad space through DSPs.

To optimise traffic, lookout for faults in their ad serving, and to provide value to ad agencies, many DSPs will also track clicks.


3rd Party Ad Servers

Then there is the ad itself. While some ads are just gifs or videos, some are much more complicated. To get these to run across the different technical needs of millions of combinations of websites, browsers, computers etc requires a special sort of company – which are called Third-Party Ad Servers.

These companies solely work on delivering ads across any set of millions of users with as few problems occurring as possible. To make sure they are doing this, they will also likely track clicks as if an ad has a low CTR on a certain site or browser etc, then that is an early indication of a problem.


Stage 4: The Advertiser

So from here, we finally get to the advertiser. While some advertisers may be happy to accept the reporting from any of the previous steps, they often also want some tracking of their own.

This is often the simplest type of tracking of the lot – usually just a specific URL or a UTM link. Whatever it is will still help the advertiser to work out which specific ad was clicked on.



When you click on an ad there are at least eight interested parties who might be tracking that click:

  1. Website
  2. Analytics
  3. Ad Network or Supply Side Platform
  4. Ad Server
  5. Ad Agency
  6. Demand Side Platform
  7. Third-Party Ad Server
  8. Advertiser


Supply Path Optimisation

The more complexity in a system, the worse that system is likely to run as there is more than can break.

Because of this advertisers and websites often do something called Supply Path Optimisation (SPO). This is a process of cutting out as many intermediaries as possible when delivering ads.

Due to this many websites will have far fewer trackers than the number listed above.

Supply Path Optimisation improves:

  • The speed at which ads load
  • The percentage of ads which break
  • The amount of money websites & ad networks receive
  • The amount of money advertisers and ad agencies pay
  • User experience (fewer broken ads, faster page load speeds)
  • User trust (less terrifyingly long cookie and privacy policies).

It should also be noted that first-party data (as in data you collected yourself) is increasingly valuable. Many websites reduce the supply path in order to keep their data to themselves.


Note: In my experience, the number of trackers on websites:

  • grows until someone notices there are too many
  • are reduced significantly
  • grows until someone notices there are too many
  • are reduced significantly
  • …forever

It’s a very common cycle.


Other Trackers

While the amount of tracking is often less than this, it can also be more.

For example, any of the above might have multiple platforms tracking the same activity for some reason (such as two advertisers partnering and both wanting statistics).

Other possible types of organisations tracking clicks:

  • Auditors/Consultants at any of the organisations listed. This includes click verification software.
  • Security Software. For example, click fraud trackers at the advertiser’s end, or malware/virus protection on the end user’s computer.
  • Spyware/Computer Viruses. If your computer is infected with a virus, there is no reason why they wouldn’t track your internet activity.
  • Campaign Optimisation Software such as for split testing, landing page optimisation, or creative testing.
  • Unrelated Trackers placed on a website. These shouldn’t track ad clicks. But with the amount of data slurped up by companies, it’s likely that some are doing it.
  • Browser Plugins – again, these shouldn’t track ad clicks, but again – it’s possible.
  • ISPs and Mobile Phone Networks are able to see all the details of internet traffic that runs through them. In some cases, they will be actively tracking it as a service.


[If you know of any other tracking that takes place as standard, drop me a line at justin@theonlineadvertisingguide.com and I’ll update this article]



The above explains all the types of companies involved in tracking clicks. The below infographic is from the point of view of the user.

It is intended to help explain all the things that happen on an individual’s computer when you click an ad. Feel free to share it.


What Happens When You Click On An Ad? InfographicClick to enlarge


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