I'm asking you about the details that make them different, and which you consider relevant for a "web with user contributions" in the way you described.
The difference is that those features would be implemented differently in a blogging context. I think that they're things that would improve a collaboration on blog to move from simply getting feedback from users as comments for the author to use to actually collaborating on something to make it better. I haven't thought about what those implementation differences would be; it'd be a lot of work.