Today Facebook began rolling out a new feature that lets you see a history of everything you’ve searched for on the social network. A list of search queries now appears intermingled with all the Likes, comments, and wall posts that appear inside the Activity Log — a private section of your profile that only you can view. via Facebook now saves all your searches to your private Activity Log
Your activity log is a tool that lets you review and manage everything you share on Facebook. Your activity log is a list of your posts and activity, from today back to the very beginning. You’ll also see stories and photos you’ve been tagged in, as well as the connections you’ve made – like when you liked a Page or added someone as a friend. Only you can see your activity log.
Facebook also stores a lot of information about you, some of which it shares with advertisers by allowing them to target you based on hashtags attached to your account.
While most of the information should not be too shocking — you do, after all, post and share your life on Facebook — there are a few surprises. Facebook gives a full description here of everything that is stored in the archives, and how to block this information from being uploaded if you choose. via What Facebook Knows About You – Business Insider.