Valve's Chet Faliszek has told Kikizo that all L4D mods will work with L4D2. Just in case you needed any more Left 4 Dead news.
"For modders, everything they make in Left 4 Dead will work in Left 4 Dead 2," said Chet.
"It'll work better if they bring it into Left 4 Dead 2 and recompile it for Left 4 Dead 2, using some of the additions we've made, but it'll work out of the box as well. We just want to make sure that anyone who's making a mod now knows that their time's going to be well spent."
What a bastard. Quick, sign a petition.