Of five points and bad karma

Recently, I got moderator access on slashdot for three days, which meant I had five points to mod up or down any post. I have been active on the forum, as a result my karma level has been fluctuating lately.
Slashdot is an interesting concept, that too a pretty successful one..a perfect example of self-sustained organically growing entity. Other examples, I can think of are wikipedia and experts-exchange... orkut had shown some promise and grown pretty quickly in its early days..but somewhere it lost track. This is not to say that I am comparing orkut with slashdot. Of course, there can't be any comparision. orkut has almost five times more users than slashdot, orkut is just one year old, while slashdot is around for 8 years ,yet, the level of participation on slashdot is much larger and much more intriguing.