Long story short, you should use TOR to maintain anonymity online.

The challenge that this faces is the fact that many sites will restrict/block access from TOR exit nodes. These forums will even make you pay a (very) small amount of BTC in order to access your account if you try to access via TOR (AFAIK this is only a one time payment).

Another major challenge is that it is very difficult for a site to gauge the likely hood that your account has been hacked. Normally a site can see that you usually login from London, England using Modzilla and if someone logs in from an IP in London using Modzilla there is a good chance that the account owner has logged in, conversely if someone logs in from Sydney, Australia with Firefox then the account has likely been hacked and additional security screening would be necessary.