Ruben posted a thread at Google Blogoscoped Forums with a screen shot showing how Google is testing slightly different variations of colors in the web search results.
Most of us wouldn't take notice to these changes but Google is obviously testing the slightly different color changes to see if they have an impact on the searcher. By impact, they are likely testing to see how users interact more or less with the search results based on the color changes.
Here is a picture from Ruben:
Do you think the slight color changes can make such an impact? I bet Google has data to prove it does.
Forum discussion at Google Blogoscoped Forums.