I have setup a pseudo-clone of perlmonks at work for work related issues and discussions for our company and we were running into a similar quandary over the issue of non-work-related or OT discussions in the sections
in reply to An OT section (again).
After much deliberation, we finally came to the conclusion that since we were trying to build a virtual community for our folks to share ideas, those people needed a virtual 'watercooler section' to discuss the off topic stuff just as they would in the real world breakrooms
Since implementing this we have actually lowered the number of "don't post that OT 'stuff'" complaint posts as there is now a good place for them to post such and those that wish to ignore the same can do so easily by ignoring that section.
I am not suggesting we achieved world peace, but the users seem satisfied on both sides of the OT isle.