Source: http://lifehacker.com/make-facebook-more-searchable-with-email-notifications-509958135
Facebook's email notifications are usually just annoying, and we often recommend turning them off. Weblog MakeUseOf discovers a good reason to keep them on: it makes your entire Facebook archive searchable.
All you need to do is turn on Facebook's email notifications, then set up a Gmail filter that automatically marks them as read, archives them, and labels them. That way, you never have to deal with them cluttering up your inbox, but if you ever want to find an old post, you can just search your email inbox for a direct link. It isn't for everyone, but if you find that you get annoyed at not being able to find old Facebook posts, it's a pretty clever solution. Hit the link for the step-by-step.
Facebook Search Sucks - Use Facebook Email Notifications as a Workaround | MakeUseOf