On top of this long list of conflict of interest problems, DoubleClick also brings Google its history of user-end privacy controversies.

FORBES: Google's TroubleClick

The social network plans to end user voting on its privacy policy, and allow the sharing of information across its services.

BBC: Privacy groups call for Facebook changes U-turn

It's understandable if the prospect creeps you out -- it should -- but the end goal isn't to invade a user's privacy (though the data mined would be significant), it's to anticipate and assist.

ENGADGET