The Electronic Frontier Foundation has published an important document to step you through the ugly planet of Internet privacy leakage. After going to my Google account and clearing and disabling my web search history (legacy shelf life allegedly will be 18 months!) preparing for their announced merging of profile usage information for (I only list the main ones here) all their services like Gmail, Docs, YouTube, and Maps, I suggest the steps the EFF has described at the link. Six Tips to Protect Your Search Privacy | Electronic Frontier Foundation.
my Wickedleaks papers go into more detail on the fatal internet flaws that make internet security (and invasive abuse) an evolving big issue.