I disagree, >>3.
<pedantry>

>Channel4 is a website for anonymous discussion on a variety of topics.

I don't see anything in there about hikkis and loners only.
</pedantry>

The only way to keep a secret is not to tell people who won't also keep the secret (eg: impossible).

>>The best solution might be to delete the whole site though.

In the case of channel 4, the cat's already out of the bag. That doesn't mean you should shoot the cat.

What this all really means, though, is that you, >>1,3, should set up a private BBS for hikkis and loners, and keep it private.