According to the website, since its creation in 2000, phpBB has become the most widely-used Open Source forum. This is quite probably true.
The great thing about phpBB is that it’s easy to install. As long as your service provider includes My/Postgre/MS SQL along with webhosting, it will install and run. It’s available in a wide range of languages, the documentation is comprehensive, and you can modify the colour scheme, or and/or install new skins, extra smilies, user avatars and ranks with ease.
From the point of view of users, the forum is extremely easy to use, and you soon get into the swing of it.
The administration control panel is fairly intuitive: adding, modifying and deleting forums is reasonably straightforward, as is creating and managing user or group permissions. However, I find the user management interface irritating, as there is no direct access to the list of users at any point; to modify a user in any way whatsoever, you have to know his handle beforehand. It would be practical to have access to a list of users, sortable by registration date or name (at least), when weeding out undesirables – of which more later. This is all the more exasperating in that a sortable user list is available from the public site.
A nice touch is that the administrator has access to the IP addresses of those online, and a little message informing him if a new version of phpBB is available.
Customisation: a large number of MODs (modifications) can be found and downloaded from the main site, although if you use a template other than the default Subsilver things can get complicated. Installing a MOD means opening up the bonnet and messing around with the code. You will normally be warned if a MOD is best left to experienced PHP programmers, which is a relief, but using MODs also means having to redo all the work every time you update your version of phpBB – with the added caveat of never having the guarantee that the MOD will work with the new version, or indeed with other MODs you may wish to install.
Sadly, phpBB does not support plugins in any way, which I consider a major weakness. MODs are all very well for the experienced webrat with time on their hands, but the vast majority of admins either won’t have the time, the patience, or the expertise to dig around in the code every time there’s a new update. This means that a large number of forums won’t have security updates applied because it’ll destroy the customisation, or MODs won’t be used because you keep having to reinstall them.
Now, among of the most important MODs are those which facilitate the weeding out and neutralisation of spammer accounts, of which there are many, phpBB being so popular that bots have been written to automatically create accounts on any forums they find: even on a very small and obscure forum I run, I get 4 or 5 a day. The sheer clumsiness of the standard user management interface and the awkwardness of installing MODs, plus the inherent laziness of the average human admin with more interesting things to do, mean that in many cases these parasites proliferate unchecked, polluting the forum databases with bogus accounts and messages, and the Internet with links to spamvertised sites.
All in all, not bad, but could do a lot better. I can’t really recommend phpBB for use on a public site, but it is ideally suited to company intranet use, where spammers and other idiots are not a problem.