The new Smash Bros. game will support up to four players online, and you can play with either friends or strangers. http://www.nintendoworldreport.com/newsArt.cfm?artid=14419 The official blog of Super Smash Bros. Brawl has finally squashed the fears of many fans, confirming online play for the full complement of four players, well over a year after the feature was last mentioned by anyone at Nintendo.
The two main online options are "With Friends" and "With Anyone". The former allows you to see a list of friends with the game; it's not clear whether the list is comprised of Wii system friends or only those who have registered a game-specific Friend Code. After gathering up to four people to play, you can pre-set four short bits of text to be used as taunts (mapped to the D-pad) during the battle. It is not clear how the taunts will be used with the Remote-Only control scheme. "With Anyone" sets up a battle with strangers. You will not see their names or be able to send them messages. Also, no battle records will be kept from these anonymous matches.
The extent of battle modes and other features to be made available with online play is not yet apparent. The blog promises that more details about Wi-Fi Play will be revealed in future updates. There is also a warning (and apology) that the gameplay speed is directly tied to connection strength, so the game may not play optimally between players who are separated by large geographical distances. In other words, the game will allow you to play matches between Japan and America... but there will be considerable lag. Regional matches are recommended for the best performance.