why do you think 2 isn't a good idea?
Not all people do it. You need to post in atleast 4 boards to reach 100 valid posts. So it is hard for some who will only post in <=3 boards or maybe 1 board.
-MZ
That is the whole point here. People who only post in one board, will still get some amount (we may discuss whether that should be 25 or 40, for example) but won't be able to score the maximum by just posting in one section. That way the advertiser guarantees the visibility in different sections of this forum.