The need to retain the search data to determine click fraud came up in the debate. If there are laws enacted that force the engines to destroy the data within, say, six months after it's collected, that could interfere with the engines' ability to detect and fight click fraud.
Arguably, the engines should clarify what their data retention and sharing policies are. Thus someone who uses them would at least be alerted not to give out personally identifiable information if they wish to keep it private.
