Forums or Chat with comments?

I have used both forums and chats extensively in my 30+ years of computer experience, and honestly I say I don't have a real preference.

Chats are postings with comments but it does not continue much past the last posting date. All comments relate directly to the post at the top of the page.
Forums can continue to discuss the points of 1 post for a long time.

So quite simply which do you prefer Chats, Forums, or would you rather there be both?

Let us know!