There is a leaderboard. But not much of what you expected it to be.
http://aos.mp2.dk/Scroll down and you'll see the highscores shown. You'll only be able to record and keep track of your kills by doing /sitelogin <forum name> <forum password> on certified servers. The list of certified servers is right above the highscores list.
The function will not work if the forums are down. And if you want to hop on a certified server whenever the site is down, just go to aloha.pk and to the right you'll see a list of servers.