A new WebmasterWorld thread reports several webmasters complaining that Google is not sending referrer information for all clicks from a Google search engine.

First reports came from WebmasterWorld yesterday, July 12th. The individual said:

Several other webmasters confirmed seeing the same issue. Zett, a senior member said, “I am seeing that as well. Not too many yet (maybe 2 to 3% of all referrers from Google), but still noticeable.”

Another person posted what he thinks it might be:

This happened before when Google switched to testing AJAX based results, which caused an uproar amongst webmasters who were unable to track referrers.

There was some discussion that Google would being back the AJAX results after they figure out a way to pass along the referrer data. Not sure if this is them testing this or something else.

Forum discussion at WebmasterWorld.

Update: Matt Cutts of Google confirmed an issue when Google was not sending referrer data in the thread. He said: