This image was lost some time after publication, but you can still view it here.

It's the "I'm working on a screenplay" of Silicon Valley: Every regular Joe's got a dot-com startup, or at least a great rough draft they've been tweaking forever (sometimes entire weeks). But a budding entrepreneur needs to research a bit before popping some flipmeat on the barby.

As service journalism to all the would-be startuppers out in the Valley, here's the checklist to confirm that yes, someone else had your idea, and yes, they did it better than you can.

Web 2.0 Mashup Matrix: If your elevator pitch includes "Gizfeedblum is like [Billion-dollar company 1] mashed with [Billion-dollar company 2]," then it's already been cataloged here. Just check Billion-dollar company 1's row and 2's column.
Web 2.0 Directory: Just because it's not a mashup doesn't mean it hasn't been done already. This week. By someone with a cousin at Yahoo. Among over 900 Web 2.0 services, one represents your crushed dream.
Complete list of Web 2.0 Products and Services: Far from complete, but this might find your hope-squasher if the first two missed it.
Lifehacker: Our superproductive sister is already using your predecessor to organize her "pics of stuff on my cat" folder or something. Search the archives for your buzzwords.
TechCrunch: And Valley blogger Michael Arrington has already praised said predecessor.

Dude. Get over it. Maybe work on that screenplay instead.