Worth caching a dynamic comments system?

I plan to build a web site where users can leave some comments (like dig, facebook etc..) I am wondering whether it is useful or not to cache comments.

Do users usually read more comments than the开发者_如何学Cy write some?

With your experience, what could be read/write ratio for dynamic comments ?

A properly-designed comments component will have the same interface whether you cache them or not, and cacheing should be trivial to retrofit if you implement it sensibly.

Start without caching, measure the performance for your actual application. If it's a bottleneck, then add cacheing and measure the difference.

Don't waste your effort until you know you have a problem.