[atari]

Patents in the US are on a "first to invent" basis -- so if someone else has done it before, then you theoretically can't actually patent it. This is different than in Europe where it's a "first to file" system.

Now the problem is that lots of people patent things anyway that they shouldn't be able to because (1) patent examiners are underpaid (2) they're overworked (3) they spend less than 24 hours on each application and (4) they only check very limited databases for prior art, which do not include the internet. Crazy, I know.