Internet forum, bulletin board, message board, forum board is an online discussion site where people can hold conversations in the form of posted messages. Unlike chat where messages are removed, message board keeps all the messages so that any forum member can reply to your messages at any time. There are many popular forum boards with thousands of members that contain a lot of useful information. If you are looking to start a forum then you need a forum software or forum script. Here is most popular forum scripts in PHP.
Most Popular Forum Scripts
vBulletin – is undoubtedly the best forum software
Invision Power Board – popular paid forum software
MyBB - is best free open source forum software
phpBB – is also popular free open source forum script
Simple Machines Forum (SMF) – Another popular free forum script
bbPress – It is a powerful WordPress forum script which must be conceder while choosing forum software.
If you want to start a small forum then fee, open source forum software might be the best for you!