If you are looking for a browser based game try darkgale.com. It's early in the game, so building a good community is the goal. The game emphasizes competition and collaboration and the features coming will definitely bring it. New content will keep coming, so your opinions and frustrations are valued. It's a game by a gamer and it isn't pay to win like the other browser games out there.
Edit: Dark Gale is a browser based RPG where characters declare their allegiance by joining the Linnean Alliance or the Zimmerich Axis. You pick between different classes and roles within each alliance and race to be the strongest, most competitive or most collaborative player in the game. Building strong relationships with key allies, friendly competition between rivals and taking down your sworn enemies are your key elements in the game in order to have fun with other people and the game.
There is no strong story in this game, but more of a side story, which is where quests come in to fulfill that idea. Quests will be the solo player and the collaborative player's best feature to take advantage of. There are more features coming into the game to bring more collaboration such as parties and guild raids. I will describe parties later when it comes, but guild raids can be formed against NPCs in the world for loot (which is distributed randomly to characters rather than the guild) and this requires collaboration. Guild raids launch within 10 minutes of its start and all members who feel they want to join the raid must be in the same position where the raid is started. Collaboration is key.
I hope you guys try it out and hope to meet you. Thanks guys!