You also need to understand that in my day job I’m a software engineer (programmer) and I build scalable websites. It takes a lot of work to do it right. phpBB and SMF work but it does mean they were built right. Not to say those programmers are bad but I doubt anybody who originally worked on phpBB and SMF would ever code something in that same manner ever again. The codebase intertwines the data models, the views, and has no templating system. The code is spaghetti and my eyes bleed whenever I have to read it.
I’ve avoided building my own forum in the past because I know how much work it will be. Enough of that, if nobody else will do it right, then I’ll do it.
VanillaForums comes the closest and has a much cleaner codebase but there are many things that I would still have to implement to run Vanilla.
If I upgrade, it will break everything. The next upgrade will be a migration to new forum software, which I will be writing myself because the current state of the forum-world is horrendous. If we don’t evolve, everybody will migrate to Quora and StackExchange.
I’m not too familiar with the SMF system but you should be able to upgrade without breaking links. With phpBB you upgrade the forum not the data. the data is in a separate dbase and is a slave to the forum software. In the beginning at the Underground we were spammed to death so I added a simple security question to the registration process and we haven’t had even one spammer in a year. The question is simple but bots don’t know the answer. “What war does the game cover?” Any doh-head knows the answer, but bots don’t. I honestly have few issues with the phpBB software.