No and here's a main reason why.
Think of 9/11. I wasnt here when 9/11 happened but i've seen the threads, and if I was here i'd be posting a lot that day. Emotions were high, people were panicking over loved ones, etc. What if you could only have 10 posts that day, and you did 8 of them before 9/11 (assume they were helpul posts and whatnot). Now you have to miss out on discussing something that affected the entire country because of a 10-post-per-day rule?
And you can't say just turn it off when something like that happens, because lots of things are newsworthy/important to some people that arent to others. The war in Iraq, Award shows, World Series, Superbowl, etc. A 10 ppd limit (or 20, or 25, or whatever) would kill any decent conversation/debates/whatever else you can think of.
Just my $.02