Only one or two, as best as I can recall, but those were privately held 1x1s in different placed So far, zero here - every one I've started has either been abandoned (often without warning via my partner simply vanishing off the face of the earth, or with warning but no definite 'yes we're done'), put on a hiatus (that may as well be permanent), or moved to another forum during the last round of crashiness/debugging. Of all the roleplays I've begun here, a whopping two are still active (and one is slow and possibly heading for another abandonment as my partner is busy looking for work and hasn't replied in some time). 

But, before I come off as all doom and gloom, let me add that the one that's still active and is going well is actually going great. Really and truly - my partner and I work great together, are friendly in OOC and handle planning well, and are both very satisfied with the story's progression, and I met them here, so.

I guess the best way to think of it is you've got to pan a whooooole lot of sand to find that gold, but believe me, it's well worth it when you do! So for those of you who are still struggling to find a good partner here, have faith - you may have to start with and be abandoned by many other players here, but when you do find a few who are committed to you and your story, it's extremely satisfying and enjoyable. I don't begrudge the ones who've jumped ship, either, it just makes me more grateful for the ones that've stayed.