OmniNet already have a NickServ who helps combat impersonation: on connect, type /msg NickServ help register. The webchat we provide have a field to type your NickServ password (not to be confused with forum password). You can then /whois people, a "logged in as <user>" line will show up if they're logged in.
We could also provide a way to change your hostname to a personalized one when you login, much like some users actually have.
Ahh yes, this works very well too.
I was referring to the EFNet side of things, however... which as we all know, is a "service-free" network (e.g. no NickServ/ChanServ).