And how is the sanity of my posts controlled ?
People will see your posts and your nick and will start recognizing you as a member of the community.
Cant I just post useless information all over the forum this way?
Yes, but you will not likely find people who want to trade with you.
Isnt this encouraging of "not so useful" posts just for the sake of trading?
Maybe, but again at least you will be recognized.
And what If I go to off-topic section to post 20 jokes in a separate well named thread ?
You keep asking the same questions. Some people are actually doing stuff like that to obtain a higher forum rank.
You have to understand that this is a precaution we introduced recently to fight of the huge amount high volume scamming attempts. People were using nicks that looked similar to moderator nicknames and tried to scam Protoshares worth tenthousends of dollars.
These guys are recognized earlier if they have to post 20 messages on the forums before they can access the trading zone.
I hope this clears up stuff. If you dont want to get involved with this forum community anyways, you can still trade at the known exchanges. The volumes are high and the fees are low.