Worth a read. This fellow has noticed a flaw in how security is – or is not – handled in Google’s approach to personal search history.
Yes, I did give my permission for someone to log in to their Google account from my laptop. However, I reasonably expected Google to log him out after a while even if he did not log himself out. Then I realized that this is probably not a bug, but rather an architectural limitation. Google cannot tell when a person has finished using a particular computer or if in fact if that person actively uses multiple computers. For personalized search to work well, Google needs to capture all of a user’s search activity. While doing that aggressively, Google became a tool for compromising my privacy.
As a result, my search results are not only “owned” by someone else, I don’t even have access to them.