I've been doing it for several years mainly because I have long-distance family and this is a way to share it with them. But I was always aware that anyone can watch it and at some point our local studio even posted the youtube links on their site. But I remove videos made more than 2 years ago or so.
I will probably do the same - remove the old ones when they start to look stale. At present they don't look that different from the new ones
What's interesting, I still have my old competition photos on my fotki site. So even though you can't see it in action, they probably give a good idea of how it looked, especially for someone who dances too.