Never heard of Tor, but you don't need it to login anonymously here. Using any browser, just click on the User CP link above to start. You want to go to:
User CP > Settings & Options > Edit Options
The first thing you will see in that section is "Use Invisible Mode." Invisible mode lets you to login and browse the forums without appearing in the "Currently Active Users" list. No one will know you are here. Just check that choice and you're good to go!