That is hard to get, usually you maybe have 200 active on a 1000 member forum.... that is a high percentage of active members, I must say.
And i think it should be 15 posts.... 5 posts isn't really much....
Okay 15 is a lot.... maybe 10. I think that They- if dedicated to their blog- should actually work for their blog.
Oh ps- lots of my small traffic that i get is coming from bloggeries- Whoot! It does its job