lim =?
average -> limit
yeah, It makes kinda sense,if you want to vote really by posts. But I suggest making a vote system by users based on rating posts. The more posts of mine you vote, for example, the more accurately you are rating me. It's an average of all my voted posts...
It has disadvantages, if you want to mark a user who has many voted posts, that's for sure... but... this would also depend on the number of posts the user has.
A user with 150 posts has the same right to be rated as the one with 400. If we had the number of rated posts in consideration, the one with 400 would probably have a much worse or a much better reputation than the one with 150.
Hope you're getting my point.