Valve 'Probably' Done With Single-Player Games (News)

Keighley (journalist) heard directly from Gabe Newell (Company Founder) and Erik Johnson (Project Manager) that:

"Portal 2 will probably be Valve's last game with an isolated single-player experience," Keighley wrote in Final Hours, "What this all means is something Newell is still trying to figure out."

Single player games outside Valve have all but disappearing, God of War had a good run with single player yet the developers are thinking on making a multiplayer mode for it as well (not sure about how this will work). Resident Evil also is jumping aboard the muliplayer bandwagon as they to are about to add a co-op like game experience.
The comment from Valve is striking, though, in that it doesn't sound like Newell and Johnson said they'd probably never ship a game that didn't have a multiplayer mode somewhere in it. Rather, they told Keighley they "probably" wouldn't make a game "with an isolated single-player experience." That would mean no more modes that couldn't connect in some fashion to other people (maybe co-op Half-Life?).

Either way Valve and other companies go. I do love singleplayer games a little better than multiplayer games unless it is just focused on that. C:SS and TF2 are both good multiplayer games; Assassins Creed and God Of War are good singleplayer games. While others such as BadCompany 2 where triumphant in multiplayer but lacked a good singleplayer campaign, same with the COD games (although the people it attracts also sways a games appearance).