In 2011, there are no excuses to use a bad platform (or develop your own).
You have a huge number of successful, proven, platforms to choose from.
We have platforms at any budget. From simple mailing lists and forums at the low end to enterprise platforms at the high end.
I dispair at organizations that complain about being stranded with a platform they don't like. The switching costs are miniscule. The benefits are huge.
Make sure you're using a community-based platform that's proven to work.