From Comparison of Internet forum software (PHP):
| Name | Creator | Current stable version | Cost (USD) | License | Threaded | User themes | Calendar | Image attachment | Unread message tracking | WYSIWYG Editor | PostgreSQL | MSSQL | Oracle | SQLite | Firebird |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| bbPress [1] | Automattic | 0.8.3.1 | Free | GPL | No | No | No | No | No | No | No | No | No | No | No |
| IceBB [2] | XAOS Interactive | 1.0-rc8 | Free | GPL | No | Yes | No | Yes | Full | No | No | No | No | No | No |
| IPB [3] | Invision Power Services Inc. | 2.3.4 | $149.99 Standard, $299.99 Business | Proprietary | Yes | Yes | Yes | Yes | Full | Yes | No | Yes ($60) | Yes ($60) | No | No |
| miniBB [4] | Paul Puzyrev & Sergei Larionov | 2.1c | Free / Paid plugins | GPL | No | Yes | Yes | Yes | ? | No | No | No | No | No | No |
| MyBB [5] | MyBB Group | 1.2.12 | Free | Other | Yes | Yes | Yes | Yes | Session | No | No | No | No | No | No |
| phpBB [6] | phpBB Group | 3.0.0 | Free | GPL | No | Yes | No | Yes | Full | No | Yes | Yes | Yes | Yes | Yes |
| PunBB [7] | Rickard Andersson | 1.2.16 | Free | GPL | No | Yes | No | No | Session | No | Yes | No | No | Yes | No |
| SMF [8] | Simple Machines | 1.1.4 | Free | Other | No | Yes | Yes | Yes | Full | No | No | No | No | No | No |
| UseBB [9] | Dietrich Moerman | 1.0.8 | Free | GPL | No | Yes | No | No | Session | No | No | No | No | No | No |
| Vanilla [10] | Mark O'Sullivan | 1.1.4 | Free | GPL | No | Yes | No | No | Full | No | No | No | No | No | No |
| vB [11] | Jelsoft Enterprises | 3.7.0 Beta 3 | $85 one yr.+updates, $160 lifetime + $30/year updates | Proprietary | Yes | Yes | Yes | Yes | Full | Yes | No | No | No | No | No |
| Name | Creator | Current stable version | Cost | License | Threaded | User themes | Calendar | Image attachment | Unread message tracking | WYSIWYG Editor | PostgreSQL | MSSQL | Oracle | SQLite | Firebird |
I made this table by stringing together the data from that article about a subset of the listed forum packages, preferring the three most popular ones and any others that were freely available, out of beta (except one that is almost out of beta), with their own Wikipedia articles, and deemed by me to be at least halfway-decent; I omitted the latest release date here, but all of them have had a new release at least in 2007.
I removed some columns of important data because they were all the same in order to save space: All of these forum packages allow flat mode and can use MySQL databases, while none can use flat-file or Access databases.