It's been a few years, but I used to play a few Warcraft II ladder games at Case's ladder. IIRC, the ladder is a ranking of players; when you sign up you're at the bottom. You challenge higher-ranked players, and if you beat them you gain rank; I forget if you swap places (don't think so), jump halfway up the ladder between you and them or go one spot above them in the rank. If you stop playing for a while you quickly slide in rank as people challenge others and get placed ahead of you.
Some problems back then were people not honestly reporting wins/losses, dropping connection ("oops") instead of taking the loss, etc.. Also since everyone wanted to play a higher rank to climb the ladder it was hard to get some players to play a lower ranked player. It's been a few years since I looked, so maybe they've fixed this stuff by now.