OK, I understand. I was not clear that this was how SUL is going to work. I thought that SUL meant that I would not have an account on all wikis, but that when I created one on a new wiki, it would automatically give me the single user name and passwd. It does seem rather excessive for every user on the en wikipedia to have an account on every small wiki. Is is not a burden on the small wiki's servers?
I think the idea is that all the wikis share a user database, so it should actually reduce the server load. At least, that's how I understand it.