Just because Hideo Kojima plans to incorporate online features does not mean that MGS3 will be fully online, where hundreds of Solid Snake and Gray Fox-wannabes battle it out in a giant arena. Kojima may just hope to allow various extras (new costumes, weapons, etc.) to be downloaded to increase replay value. Or, as Echo stated, he may attempt something more revolutionary.
I\'m certainly interested in seeing what he has planned. Personally, I think I\'d enjoy a Metal Gear adventure that had nothing to do with Snake, Raiden, or any other MGS components, except for the stealth/action gameplay. Something entirely new.