Uhm ok tell me if you like this scenario:
* I'm fed up of my employeer so I'm sending tons of jobs applications from my personal gmail account
* I dont write these mails while at work, but sometimes I login on google services for doin some work-related stuff (let's say use keyword search tools)
* I forgot to logout
* I start searching stuff on the net with my chief for our vmware project and instantly google suggests me as a perfect match my application letter sent to vmware HR
* Thank you google I'm almost fired :)
of course in this case I should've logged out from google, but I'd prefer to possibly opt-out this kind of stuff...