Lisa is correct. 
Posts are actual entries in the forums, comments are all over the place, in the polls, the download section, journals, etc.

zaphod can correct me if I'm wrong, but I think comments are different than posts. 

Comments are replies to news items or the poll while posts are postings to the forums.

How come there is a difference of 8 in the number of comments posted tally between my profile and the number shown under my avatar when I post a comment?