Cool discussion!
Actually, maybe I'm a little delusional, but the forum seems to have pretty good activity from my point of view. It never feels 'dead' to me (PIXELATION WILL NEVER DIE!!!1!).
Decisions on the blog need a clearer definition of what the blog would contain. I think it's the kind of thing that would work better if we had a LOT more activities. For instance, having hidden collab entries as Zoggles suggest would give a steady stream of blog posts, since each collab "Reveal" would be a really cool thing to see on the front page. I also like Zoggles idea for 'easier' activities. The edit idea is really great, and could be a recurring thing.
But I absolutely love Helm's idea for focusing on adding participation re-enforcement mechanisms to the site. The thanking/karma system is elegant and should definitely be done. But I also get crazy ideas like having some kind of counters or records that show how many collaborations and activities a person has participated in. Kind of another aspect to the person's community participation besides karma.
I say shelf the blog idea and let's focus on participation reenforcement and activities. A blog is a pinboard for community spirit and activity, which appears to be something we could use a lot more of.