|I've been skating vert since around 1987 or there abouts. Until recently, I only knew of Alan Oates, who was the one that inducted me into vert quad roller skating. Since discovering all of you true die hards here online, I'd have top say that my estimate of our numbers has risen to maybe 30 active skaters world wide at any given time.
I know that there are more...total, but not during any one year. If you include roller derby girls who participate half a$$ed, then that number might go into the hundreds. However, I've never known any derby girls that are serious about vert skating. It is always off and on with them.
My top guess would be thirty five world wide.