For what it's worth, here are the three browser games I'm playing now:

Echo Bazaar: a story-card based game set in a mysterious, steam-punky, humorous London with Clay Men, Rubbery Men, and devils.

Misfortune!: a Bard's-Tale-interface-like game set in a mysterious, steam-punky, humorous seaside town with pirates.

Godville: a text/web interface game in which you don't actually do much yourself -- but the hero who worships you goes on quests for your glory, builds a temple to you, and does all sorts of things like that. It's set in a humorous kingdom with puns. You can encourage or punish your hero, but that's about it. Nonetheless, there is a community of "players", and it's fun to read