What is the Google cookie?

For those of you who're new to the concept, a cookie is just a piece of info stored by a server on a user's computer for future reference. The Google cookie holds info regarding user preferences, and also a unique ID, so that a user search profile can be built on Google's servers. This is how Google created the personalized search. In this article I'm going to refer to a different Google cookie - the one that's created by Google AdWords.

PPC campaign conversion tracking - AdWords VS Google Analytics

Google provides two main methods to track conversion in AdWords campaigns. One method is by implementing a conversion code inside a specific goal page. When this page is reached, the code is activated and a conversion is counted, shown later in the AdWords GUI.

The other method is by defining goals in Google Analytics. A goal is defined in terms of destination URL - once a specified URL is reached - a goal is counted.

The basic difference between these two methods, is that the AdWords conversion tracking code is good only for counting conversions made by users who clicked on the AdWords campaign ads, while Analytics goals allow you to track conversions made by any user, no matter where they came from.

However, there's another difference between the two methods, and here things become a bit messy...

The Google AdWords cookie

When a user clicks on an ad, whether right to search results or on an AdSense site on the content network - a special cookie is stored in his/hers computer. Next, when the user reaches a page under the destination site that has conversion code implemented, the code generates a conversion. The most important fact to understand here is that this wouldn't happen for a random user - only a user holding the cookie will trigger new conversions. And here we reach the point of the article. Let's say that a user clicks on an ad, lands on a site, checks out a few pages, but doesn't perform a desired action that triggers a conversion. Now, lets say the user returns to this same site directly, or via a different referral at a later date. This time the user performs the desired operation. A conversion will be counted, even though the user didn't perform the wanted action as a direct result of clicking on an ad. Important to note here that as for the Google Analytics system - in this case a conversion would be counted, but the conversion sources would be credited to the actual source (whether direct access, or the specific referral) - and not to AdWords. Thus, it's a common situation that for identical definition of goal both in Analytics and in Adwords - the Analytics system will show less AdWords leads than the AdWords system. A somewhat comforting fact is that the spoken cookie is stored only for 30 days. In addition, users may disable cookies altogether in their browser - for these conversion won't be counted at all in AdWords.

Why Google does it?

The answer here is simple - to take credit for conversions, make advertisers happier and eventually push them towards spending larger budgets on AdWords. As to the integrity of such a policy, I think that it's clear that Google pushes quite a lot on this one, and in some people's opinion this would be considered as fraud. I'll let you be the judge...