This depends on the game your are playing. Some allow this, and some don't.
256 players maximum can play in one match.
yes
Yes
Online you can get up to 256 players, but if you mean the whole community you'd have to look that up.
It depends on the game, but 7 controllers can work on the PS3 and some games have more than 4 players although many only have a single offline player. Online MAG may have 250 players i think 2 players
yes you can play 2 players online on world at war on the same ps3 screen
no
No, PS3 players cannot play with Xbox 360 players online.
To play with multiple people on one PS3 you will need one controller per person. Link all the controllers to the PS3 and then have each player turn on their controllers. Play a game that allows enough players to play at once as you have people that want to play at the same time. You will now be able to play multiple people on one PS3.
No, but you can link the Vita to the PS3 console
Two players
four players
No. PS3 and Xbox has different servers.
No you can not. If you play a game on a PS3 the game limits the number of players. Just because you connect a single PS3 to two TVs does not double the number of players for that game. You can play a PS3 in an appliance store and have the picture on 100 screens with only a single player, just like they could have the same Blue Ray movie playing on every set in the store from a single PS3 console or Blue Ray Disc Player.
yes, if both the players are on the same team.
2 players
The PS3 connects to the Playstation network for online players and it is region set. The web browser is worldwide, but for game play the PS3 will only play within the region and only other PS3 players. Xbox 360 and PC games are not even compatible with the PS3 even if they could play.