A little of topic: security and anonymity question

[German <gentgerman@gmail.com>]

I had some discussion on some message board. After a while I got banned
for no obvious reason. So I have decided to create another account with
a free proxy, cleaned my cookies and continue to do some conversations
with a members with which I have enjoyed talking. I successfully
created account with web proxy, could logging in, but can't post on the
message board. The message I got was that I am not permitted to post.
So, I believe that the server can identify me somehow. Any ideas what
can be done in this situation so I can post? Thank so much for all of
your insights.