I use HaloScan for my commenting for the ease of use and managerial side of this "blog." Here is a few FAQs.
Q: How big can my comments get ?
A: Currently, there is a limit per comment with an unlimited number of comments per comment page.
A: There is no limit per comments.
Q: Are there any smilies ?
A: Yes. In fact you can click on the question mark in the comment page, which will bring up a menu allowing you to click on the smiley you want, and it will also show all the html tags that you can use while commenting.