Cooking 2.0: The real recipe database

This idea is somehow so straightforward that I'm almost sure that it exists somewhere. But I haven't found it yet...

I love cooking, and I own a considerable amount of cookbooks. But most of the time, when I'm cooking just for me, I don't use the books, because I haven't planned ahead, but just bought stuff that looked good in the store, without really having an idea what to make with it. So I find myself very often in my kitchen, looking into my freezer and wondering how I could combine all the stuff that's in there (or at least most of it) into one dish.

That's were a web-based recipe database, a real one, would come in handy. And with real I mean a database that allows users to enter a number of ingredients, and maybe a limit on preparation time, and then returns a list of recipes that match all the criteria. While there are a million recipe sites and blogs out there, I haven't found something like this - but I think demand for it would be huge. Collection of recipes could be easily crowdsourced, users could rate and comment recipes... the usual 2.0 stuff. And revenues would come, of course, from advertising. The site could also be interesting for restaurants who, instead of just buying ad space on the site, could upload a few of their recipes and hope that they "go viral", which would probably attract some guests.