Because it's better than making tons of new threads for each game you're excited about. >_>
Anyway, I'll just start by saying that I really don't get why people are mad at Nintendo or at least say they totally ****ed up. They announced a load of great stuff, such as Wii Sports Resort with the Wii MotionPlus, Wii Music, Animal Crossing: City Folk with WiiSpeak, Grand Theft Auto for DS, Spore Creatures, Pokémon Rangers (even though most people don't care about it)... There's also MadWorld that they didn't mention, which is gonna be awesome, and WiiWare games like LIT which I can't wait to hear about. Not to mention the Mario and Zelda teams ARE working on new games.
Microsoft announced a load of interesting stuff, but most of it didn't even involve games, and they ripped off Miis with their Avatars, and the Eye Toy with You're In The Movies. Still, most of what they showed seemed interesting, especially Fallout 3 and Resident Evil 5 (I really find Gears of War 2 too similar to the first one, from what they showed). And Final Fantasy XIII was a nice surprise, although the fact that it's a port means the frame rate and graphics might be lower than the PS3's version.
I didn't really watch Sony's conference, because the guy started talking about their history, sales and such, and I found it boring. The only game which intrigued me is flower, Resistance 2 just looks weird. Then again, I don't especially like science fiction stuff and First Person Shooters. Using Little Big Planet to show their stats was neat, though.
Overall, I really don't see why anyone would be disappointed at any company. Just because you want a new Zelda or Halo doesn't mean you can't take a break so they actually put some effort in those games. You can't ask someone to launch a game every two years so easily, and leaving them enough time to work on them and polish them is a lot better than whining and complaining about it.
Anyway, talk about E3 goes here.