I have to say, that last summer I came up with an idea of creating an "idea forge", where everybody can not just blog and comment, but also keep some "levelling". The main idea is science. The core is posting own explorations. Comments are supposed to add additional info, which explains\tries to explain the exploration. Also, there can be so-called "versions" - "upgraded compilations" of original idea (or a previous version). Well, I like sci-fi films amd I know - so do a lot of people.
Anyway, for Your ease, i'll shrink my words into a little list:
* MMORPG-influed large collective blog for sci-fi fans, which want to see themselves on roles of scientists,
* An archive for curious facts of science,
* Different kinds of scores (for different kind of operations)
* Real researches
* "Versions" of articles (yes... some flavour of Wikipedia)
* Discussing the famous theories (quantum one, for example)
* Special services for hi-level "scientists" (like creating own disciplines or posting highlighted posts. Probably, buyable ones.)
* "Invisible" karma (watchable for its owner only)
* Different categories (math, linguistics, psyhology) and "custom categories" (for hi-levels only, ha-ha)
* Some built-in online services (like page translating, photo browsing etc.)
P.S. I called it "idea forge" before getting learn about the "ideaforge.com" as the sample page of WordPress blog.
P.P.S. Yes, please, post it on the "ideaforge.com" domain.