This isn't going to do anything. If Episode 3 is so delayed because of production problems, then it suffers the problem of all vaporware and it's not going to be made any faster just because of passionate fan demand.
And if there's some other reason why it's not coming out, like, say, Valve correctly assuming that they would make more money by simply continuing to release more Left 4 Dead games which can be enjoyed by millions of gamers who don't even know who Gordon Freeman is, then this effort still isn't going to do anything. Valve knows exactly how strong the demand for Ep3 is or isn't, and they've made it clear that the game (and consequently the community of fans waiting for it) are not a priority to them.
This is why it's a mistake to become too much a fan of any one series or company. They might produce some brilliant stuff when they're bright-eyed idealists new to the industry but once they're settled in and have their obligatory pool of money to swim around in, things change. It's inevitable.