Well from what I understand Activision is buying up all of Vivendi's game production branch, which includes Blizzard. To be honest they were the only genuinely successful branch of Vivendi, imo. But the new name will be Activision/Blizzard or something similar, so Vivendi lost its name although I think it's controlling a majority of the shares in the merge.
I'm a little worried. Not terribly, I don't think big companies are all evil by default, but Blizzard is especially not-evil in their publication philosophy, aka "We'll release it when it's done" not "We'll release it full of bugs to coincide with a movie release date." Or "we'd rather throw away all the progress we've made on Starcraft Ghost than try to recoup our losses and release a terrible game."
The reason they've been able to do this is because the suits (guys with money) let the ponytails (creative folks) and propeller heads (coders) call all the shots, and had a really great working relationship with each other. No one ever has to tell anyone else to screw themselves due to the fact that they agree that quality will win over quantity, and it has. Vivendi didn't care as long as the checks came in on time, and they did.
Activision will now be calling the shots, and they have a much longer track record of releasing buggy games and inferior products just to get their money back faster, which I think is a bad strategy in the video game market. I'm not saying it's evil to try to keep your company afloat by throwing out a few shotgun method games (fast release low budget and quality), but I think that gamers are willing to wait and pay more for something they'll play longer and not have to patch ten times after they've installed it (or in the console world, a game that doesn't require four people with their combined eight thumbs to properly navigate the camera).
Just my 2c.