I can envision a system where 10-minute batches of posts are "mined" in a new PoW chain that stores the forum database. Of course it would have to come with a "premine" of all the old posts. There are certain sections of the forum that I would omit entirely, including (but not limited to):

- Marketplace
- Politics & Society
- Off-topic
- Archival
- Marketplace (Altcoins)

Cutting out these sections - along with all images - would reduce the initial database size by at least half, I'm guessing. Would be a fun project; if I had all the time in the world I'd probably try to launch it.