The Guild is "a web series about a group of online gamers". Felicia Day, creator of the series and the character Codex, was the love interest in Dr. Horrible's Sing-Along Blog. She mentions the Guild in the special feature 'musical commentary' for the show.
And it's worth checking out. The series follows 6 gamers for whom the game is everything. It starts when Zabou, their gnome warlock, shows up at Codex's house, wanting to move in with her because of their online chemistry. They've never met in person and that, combined with her therapist's suggestion and some other antics, convinces Codex that the Guild must meet in person.
The show is less about gaming and the fantasy world they share than it is about their relationships and lives outside the game.
They also do holiday specials and have a great music video: Do You Wanna Date My Avatar. It's taken from their youtube site.
And if you like this, you'll probably like Unforgotten Realms, about two gamers and their innumerable quests. The cartoon peters out towards the end, ultimately going nowhere, but the first 2 seasons or so are a lot of fun.