How does piwik know where you ranked for a query?

Hello Youngers

I’d like to know how piwik knows/web analytics knows where you ranked for a keyword.

My only idea is that the search engine referral passes along some kind of code bit that you guys have already decoded to be the position in the search engine page results.

I’ve seen this happen more frequently with statcounter, but piwik also notices this every once in a while.

Thank you!