The one you are using here at the warrior forums seems good to me

Do you know what software is used on this forum?

it's vBulletin, it's not free though.

google it.....you find best results....

There was a time I would have not even hesitated to say vBulletin, but ever since they were sold and adopted this funky new pricing structure of theirs i have abandoned ship. While I still haven't found a perfect replacement I think that MyBB is really quite suitable for the time being.. and.. free.

your question is very nice but I am unable to find any link for forum software, so kindly help me in this aspect.