Founded in 1996, DoubleClick is an established advertising provider that provides ads on such big name sites as MySpace, The Wall Street Journal and America Online. Unlike Google’s own advertising system, Adsense, DoubleClick forms direct relationships with advertisers and provides the software and technology to have these ads published on sites.

The software they have developed helps the sites displaying the ads to maximize their revenue and helps the advertisers manage and assess the effectiveness of their ad campaign. How do they do this? They put a cookie on your computer that tracks your web surfing behavior.

Of course, cookies are a fact of life on the internet and not necessarily a bad thing. The DoubleClick cookie only tracks non-personally identifiable information about you which means that the information they collect is not enough to identify a particular person - but your surfing information can be still be tracked.

Generally speaking the information in a non-personally identifiable cookie includes but is not limited to your IP address, browser, location, local time, date, operating system and what pages that you viewed on the internet.

How is this information used by DoubleClick and their clients?

The profiled information is used to determine which ads should be displayed to you on a website. For example, if the cookie tracks that you’re a frequent visitor of sports sites when you visit a site that serves ads through DoubleClick, you’re likely to be shown a sports advertisement. The cookie is also able to determine which ads you have already viewed to ensure that you’re not shown the same ads too often or repeatedly

The key criticisms that DoubleClick has received for this strategy is that not only does it violate a web user’s privacy, but that the information that they collect can then be possibly linked to other databases in order to “match-up” the information and identify specific users. This was of particular concern in 1999 when DoubleClick formed a relationship with Abacus Direct - an offline catalog company. Concerns were raised that it would be possible to link up the previously anonymous information with personally identifiable information. DoubleClick was criticized heavily over this deal and the service integration was subsequently canceled.

Keep in mind though that DoubleClick doesn’t actually own or use the information that they collect - their clients do. While DoubleClick has a fairly stringent privacy policy after the Abacus Direct deal, once the information is in the hands of their clients…..how it is used is anyone’s guess. However, DoubleClick has and uses aggregate data of user behavior.

For a start, the aggregate data of user behavior combined with Adsense’s existing contextual technology will probably mean that displayed ads will be able to become even more directed and effective with an increase in how relevant the Adsense ads are to your interests and surfing behavior. For Adsense publishers, this will quite possibly see your earnings increase significantly.

As the advertising that DoubleClick displays is in quite a different area to Adsense, the acquisition also makes Google quite an online advertising powerhouse. It’s quite likely that more options will be available to Adwords publishers and they will be able to display their ads on platforms not previously available.

However, in a somewhat darker side of the equation, Google now has access to a lot of statistical information about surfer’s habits and demographics. Combined with the information that they already collect through the Google Toolbar and through the use of their search engine, they have an amazing data set from which they will probably be able to predict what you’re going to search for before you’ve even opened your browser. To prove DoubleClick’s reach - check your cookies on your computer - there’s a good chance that there’s one from DoubleClick.

Further Reading:
NY Times - Google Buys DoubleClick For $3.1Billion
Google Press Release - Google To Acquite DoubleClick
DoubleClick - Frequently Asked Questions
Wikipedia - DoubleClick
Google - Does Google Toolbar Track Web Surfing?