Google Mobile Search started to display short text ads in the middle of the search results page. The mobile interface mixes web search results, news, images and local businesses, but Google displays the ads after the list of regular web results. Google separates the ads using a different background, but it's weird to see the ads mixed with search results.
Here's an example for the query [love] as displayed in Opera Mini:
Sergey Brin said in an interview from 2004: "One thing that's important to us is the distinction between advertising and pure search results. We make it clear when something is paid for. Our advertising is off to the side and in a couple of slots across the top. Ads are clearly marked. There's a clear, large wall between the objective search results and the ads, which have commercial influence."