Google has worked hard to create technology that makes the advertising on our own sites, and those of our partners, as relevant as possible. To date, we have shown ads based mainly on what your interests are at a specific moment. So if you search for [digital camera] on Google, you'll get ads related to digital cameras. If you are visiting the website of one of our AdSense partners, you would see ads based on the content of the page. For example, if you're reading a sports page on a newspaper website, we might show ads for running shoes. Or we can show ads for home maintenance services alongside a YouTube video instructing you on how to perform a simple repair. There are some situations, however, where a keyword or the content of a web page simply doesn't give us enough information to serve highly relevant ads.
We think we can make online advertising even more relevant and useful by using additional information about the websites people visit. Today we are launching "interest-based" advertising as a beta test on our partner sites and on YouTube. These ads will associate categories of interest — say sports, gardening, cars, pets — with your browser, based on the types of sites you visit and the pages you view. We may then use those interest categories to show you more relevant text and display ads.
Advertisers have asked for this targeting forever and Google is happy to oblige. What's unclear is whether this move--or other targeting efforts--will raise a long-term ruckus. My hunch is there may be initial concerns and then users will just forget about it.
In advance of what could be a targeted ad firestorm, Google given users access to their profiles, allow them to edit them and opt out of the program. Google is providing a tool called Ads Preference Manager that allows you to delete interest categories. There's also a plug-in to maintain your opt-out choices.