Just to emphasize, popularity IS important. PhpBB can be set up by any inexperienced webmaster and includes ready-to-use eyecandy for those who want it. To do the same with OpenACS, you have to be more of a geek.
Let's not criticize, but learn those things that are good over there. The question is, how and if we can easily adapt some of the qualities/conveniences of phpBB into OpenACS, without losing anything in OpenACS.