But what about all those in different time zones? Freezing the site for periods may make it tricky for people in some places to contribute at all.
The comments won't work as well if they aren't done in real time in the current format. One possible solution would be to add a separate section for active comment threads. This might serve as an acceptable way to slow them down, or keep them visible longer. However, the real time comments are a large part of what makes this site addictive, but it's also what provides a fair amount of the value.