There isn't a way to search for other users right now but you can, for example, see users you've referred with links to their profiles. I might add search for users in the future (especially if more people request it), but don't have plans to any time soon. I'll take this as feedback and prioritize accordingly though!
I was wondering the same thing. My daughter and I just joined, thinking that we could follow each other and be connected. It would be an awesome feature :o)