I had heard that Myspace's new video service was doing well, but some new data from measurement service Hitwise shows that it's outpacing YouTube by some measurements. I haven't checked with other measurement services yet, but plan to. Hitwise, is talking about market share of visits. And the service is perplexed, though, because it's showing such a huge spike in traffic, though it's not impacting YouTube.
A good chunk lf YouTube's traffic (Almost 25% estimates Hitwise), comes from the video happy folks at MySpace. Which is what's interesting about following the development of Myspace video, to see whether its growth at some point starts impacting the popularity of YouTube.