The third type of subsite on this website is the message board. I'm sure many of you looking at this site have used one before. I've always liked using them to communicate with guests on my website. The ones here are fairly basic, as far as message board software goes. They get the job done, though. For those of you who make your own, you get the added bonus of having the entire website user base already registered (you just have to convince them to pay you a visit).
On all message boards (and most other large text areas), you can use simple BBCode to format your text.
To check out an example of this type of subsite, check out the Support Board. There is a Demo message board you can test drive here.