I must again confess that I don't understand the appeal of a separate forum: what's wrong with the thriving comment sections on each post? Isn't it best to have all the discussion consolidated in one place? (Also, contra Joseph, I prefer the current flat format over a threaded alternative.)
The only problems I have with the current setup are the pagination of 50+-comment threads, and the inability to directly link to comments not on the first page of a thread. (When I follow such a link, I just get sent to the first page.) One would imagine someone at TypePad should be working on the latter problem, which seems like a major bug. Or is it just my browser?--anyone else experience this?
There is no rule against commenting more than 3 times in a thread. Sorry if anyone has gotten this impression.
However, among the 10 "Recent Comments" visible in the sidebar at right, usually no more than 2, rarely 3, and never 4, should be yours. This is meant to ensure no one person dominates a thread; it gives others a chance to respond to others' responses. One-line comments that quickly correct an error may be common-sensically excepted from this rule.
You need not refrain from commenting, just wait a bit.