I had similar experience with Swapnote.
I just randomly drew something, then other guy replied with continuation of the story and we hit it off and it went on for ten or so panels.
I think it started with some kind of retarded picture of a girl or something with a bow. There was something with a dog humping her leg or something i don't even remember. Then it sat on park bench. Then other guy drew a tentacle monster right beside the the bench, and i drew it eating the girl. A few drawings later we had TMNT turtle in a bar meeting that crudely drawn ctullhu-like tentacle monster and drinking beer together. Then they ended up in bed and then i in a fit of inspiration i drew that monster being blown from inside by that eariler girl alien style, on the next morning while turle was still sleeping.
The last pic was angry TMNT turtle showing that little girl way out, like "GTFO! You killed my monster".
Yeah... Pretty stupid but amusing.