I very much doubt there are anywhere near 3000 active players on this site - the number is probably closer to 400/500. Therefore, if you play enough and play well, you should be able to get yourself onto the board.
Also, I'm not sure if this still works, but back when I wasn't on the leaderboard if you scrolled to the bottom you would see your name and position, regardless of you not being in the top 150 (or 100, as it was then).
The new rating system is what came of
threadID=38097, but if you don't want to read through the 500 posts, what it essentially does is takes into account how good your opponents are when scoring - so if you were to win against the people at the top of the table, your score would be raised a lot more than beating those at the bottom. If you feel you would be able to do well, playing against good players is a good way to raise your rating.