Actually, it seems that the behavior died down since April 30th. I’ve maybe seen one or two more after I wrote this post.

However, I could not see a pattern at all - it seemed to affect Firefox and IE browsers, which made me suspect there was some change at Google Web Search, like the iGoogle launch.

So I still can’t figure out what’s going on. It could be a defect of certain browsers that they are replacing the referrer property with those redirects. Joy — is there any pattern in the reported browsers of these strange-referrer visitors?

This is of interest to me since Lijit just introduced a feature last week which depends on grabbing search terms from those referrer fields! ( http://www.lijit.com/node/358 )

I just searched for my website, clicked on the link, and the referrer string that arrived at my Apache server was in the old format, with the search terms in the referrer URL…

1. Go to Google, search for “cleverhack”.
2. Observe results, hover mouse over first result, note URL in Firefox status bar.
3. Click and hold down on the link for the result.
4. Observe changed URL in status bar.

Presumably, this could be used to track which results people click on for a specific search, which would improve Google’s search results.