If you're getting e-mails from spambots, there's little we can do to prevent that, except recommending you not to publish your e-mail address online.

As for registrations, that's a problem and at this point the only semi-viable solution would be to have everyone who wants to register send me or another admin a message, as we'd disable the registration form. I say "semi-viable" because it's very cumbersome for both the admins (who are all kind of busy with other things, at least I very much am lately) and the users.

As an aside, "surely something can be done about this" is easy to say but it is in fact not that simple to come up with a solution that blocks spambots while not hindering actual users.