Oh what topic do we have to post. Posting for 1 month is bit long instead you can buy domain, which should be the better replacement.
Actually it's easy to post there. You will be given HB points for posting in almost all sections except advertising. But posting in webmaster and web hosting section you will get more HB points. Actually I used to post only on their web master and web hosting sections.

You need 900 posts to get free domain. Maximum per day you can earn 40 hb points, so if you post in the sections where 10 HBs per post i.e. webmaster and web hosting sections, you can get that 40 points with 4 posts. That means you can get free domain within 22 days. So it's worth trying it.