Problem:

You are browsing through stuff on the internet.
After a while you remember something about something. You want to get back to it. But cannot find it.

I suggest:
A web browser plugin (or whatever it is called) that stores your last day/s i a local database to search through.
Come to think of it – as it catches your logged in pages, would even allow you to search in pages where you are logged in, something that google/bing/insertyourfavouritesearchengine doesn’t do.