Personalized Google ads from Wiep illustrates how Google is personalizing ads for people based on their previous search query.
For example, you can do a search for weather forecast, then conduct a new search on holiday in spain, and then do another search on weather forecast and you should then see ads for weather reports in Spain.
This type of personalization first started to be noticed back in April, as discussed in a WebmasterWorld. But that thread lacked actual examples, which the Wiep post provides, as does Ben Murphy in a separate post.
What’s Google doing to make this happen? Google sent this:
What you’re seeing is that we look at the user’s previous query and see how well it intersects with the current query. If it’s significant, we’ll use it to help targeting on the current query. We simply look at what’s in the referring URL (every time you load a web page, the HTTP header includes your previous URL as the “referrer”).
For more, there’s also discussion going on at our Sphinn social news site: Personalized Google Ads: Previous Searches Influence Ads You See.