Quoting the information presented on the rules page:
Not every forum will increase a user's post total. Certain forums are set specifically not to increase the total to combat users who spam to enable the marketplace as an advertising venue. At the time of writing, forums which do not contribute to the post total are: General Discussion, Member Introductions and any of the Talkfreelance Marketplace forums.
and
Members must have ten (10) posts before advertising within the marketplace
There may be some contradictory posts around which say 5 posts are required, or don't make mention of some forums not counting towards the post total, but the rules page is the most up-to-date.
Also note that because the majority of your posts have been in Member Introductions or the Marketplace, they have not counted towards your total post count. The only forums which
do not add to the post count are Member Introductions, General Discussion and any of the Marketplace forums. The other 27 forums do increase your post count as normal.