Currently there is no way to search for other users on the site. However, it is a feature that we know a lot of people are interested in so hopefully, at some point, users will have the ability to do so.
you can look all you want; i don't know if a person keeps his/her username or changes it. most websites have privacy tou policies. most websites are obligated to protect it's users. go to the forum as the above poster suggested.