I'm using my multiply account as a spiritual journal--some of those entries are being cross posted here. I also am able to load Youtube videos in, the photo gallery is easy to use, and in general I'm liking it. It's free, the ads are minimally invasive, the interface is easy to use and learn, and I find I'm really enjoying it, unlike Myspace which I rarely use, or some of the other blog sites. I'm not leaving LJ or anything like that.
It was worth the trouble just to use as a back up to LJ, really.