The library provides the client.SetScore() and client.GetScore() procs. These procs are meant to be similar to this feature request. The SetScore() proc takes an operation so you can, for example, add 3 to an existing score's value with a single call to the proc:
client.SetScore("points", ADD, 30)
The first line shows the ADD operation. The second shows the MAX operation, which would be used to keep track of the highest level a player has achieved. If the specified value is larger than what's currently on the hub, the hub's value is updated. This way the hub's score is only updated when you pass it a larger value. The last line shows the MIN operation, which is similar but only updates the hub when you pass it a smaller value. You could use this for keeping track of the player's record times in a racing game.
The library also includes a world.GetServers() proc, which returns information about publicly listed servers for a particular game. You can either pass the game's author and name as arguments (author first) or pass it no arguments and have it use world.hub by default.