After treading through the sea of L4D2 boycott stories and the swarm of comments they spawn, I'm left with the impression that some people don't get what the problem is. I believe the reason L4D2 is upsetting the fans is that it will segment the community. A good example is the transition from Counter Strike to Counter Strike Source. Except that CS Retail came out in 2000 and CSS came out four years later, while L4D and L4D2 are only a year apart. So while CS fans could at least bite on the idea that CSS was evolutionary, this sentiment won't fly with L4D.
The L4D community is still maturing and eagerly anticipating new content. There is no concern over whether that content will be free or pay... just that there WILL be more content and that the community will stay together. This has happened before in the Valve ecology (Team Fortress 2) so it is not unreasonable for fans to expect similar behavior. However that's not how things unfold it seems.
Suddenly, at the "Event of Events" in gaming, Valve announces a whole new title and labels it a sequel. And it comes so soon!? Is it really unreasonable for people to feel anxious, upset, confused, maybe even cheated? I know I do. I feel a little cheated that I bought L4D and I absolutely KNOW that I'll have to buy L4D2 to stick with the community. And you know what, the purchase doesn't upset me. What upsets me is that the L4D content is going to be forgotten... at least that's what everyone was made to believe.
When speaking with others on this issue, I always brought up the same points. I believe that Valve really should perform some kind of magic and allow L4D and L4D2 content to coexist. Either allow owners of both games to play together, or allow L4D owners to "upgrade" to L4D2 and be able to play campaigns/modes from both games seamlessly, or simply include all of the L4D content in L4D2 (I think that would be easiest). In the latter case, that should allow L4D owners to play the original campaigns/modes with L4D2 owners and this will keep the community together while maintaining the status of L4D2 as an "upgrade" to the original and not a replacement.
People love L4D and I'm sure they will love L4D2... but the original should not be replaced and forgotten, it should live on. And the consumer should be given options that at least sound fair. Valve has done this before, so I know they can do this again.
After reading this and this I am starting to think that Valve is just really horrible (occasionally) at communicating the right things at the right time. And because they have such a vocal and passionate community of gamers (something they shouldn't forget) things can and have gone out of hand. I'm looking forward to things unfolding in everyone's favor. Hopefully there will be more good news to come and we'll all be happy shooting zombies in the face with our friends (the way it's done best).
That's my two cents, I'm glad I got that off my chest. I'd like to know how everyone else feels and if anyone shares my thoughts on this.