For a long time, I have desired a search engine that would limit itself to searching sites that I had bookmarked. I get frequent "must learn everything about this subject" obsessions, which always make me curious to discover what my favorite bloggers and media sources have written about that topic. But it's tedious to search my favorite websites, one by one, to see if they contain any relevant information--and a basic Google search always turns up a lot of irrelevant stuff, e.g. innumerable websites that want to sell me DVDs of the actor that I was researching, rather than sites with intelligent commentary on the actor's films.
I convinced myself that a search-only-of-my-bookmarks was logistically impossible to program, or, if it were possible, it would entail such an invasion of privacy (because the program would have to look at my hard drive to see the personal bookmarks stored therein) that it would be too frightening to use.
But it's almost the second decade of the 21st century, so why be so defeatist? Naturally, the magicians down in Mountain View have anticipated the desire for a specialized search feature, and created a tool for it. I am notoriously behind the curve when it comes to technology, so most likely you already know about this... but if you don't, I present to you Google Custom Search.
It's not quite as simple (but much less privacy-invasive) than a program that would automatically know, and search, the sites in my Bookmarks folder. Instead, you have to give Google Search a list of the sites that you want it to check. But of course the explanation of how to manage your custom search engine is easy to understand, and the searches are lickety-split.
I'm now tweaking my own custom search engine--called "Marissa's Arts & Culture Engine," or MACE for short. It might be a dangerous tool, when it comes to encouraging my information-hungry obsessions, but I am glad to have it!