I don't know if it could help the world, or even care. I don't know if it would work either, but it sounds most amusing and I would be willing to be a part of something like this.
Do you think guild sounds a bit childish? It reminds me of games...and what you're trying to accomplish is no game. And Web-assassins is a pretty straight forward name, it leaves nothing to the imagination.
If you do leave the name then what about Web Assassins Squad? Or W.A.S. Since you take targets out i think that would be more appropriate.... it being past tense and all...
I do indeed like your idea and I hope you broadcast it elsewhere as well. My issue is that I would maybe not agree on the target. Or it sounds fun and actually needed as the web has shifted so much into NT mode and the good sites/products are pushed back by the bigger commercial actors. The site I would go for is no more or it would been my first target. ;))