Launching one online community is hard. Launching 3 at the same time is just dumb. You can’t concentrate your effort if you’re launching 3 online communities.
If you want to launch multiple communities, especially if they’re related, then launch sequentially. Begin with one community. Build up that community then leverage this community to launch the next. It’s an art that Martin Reed of Community Spark has mastered.
Martin launched JustChat in 2000, later bought Soap Forum in 2006 and, finally, launched Female Forum in 2008. Three related communities with an audience overlap over the course of a decade. That’s smart thinking.
Launching communities for your organization’s different product segments is smart. Just launch one at a time then leverage that community (members, topics, experience, staff) to launch future communities.
It might even make sense to spin the most popular threads/topics into their own sustaining communities.