A new online highscores system for Game Maker has been launched.
Created tables can be viewed directly within your game (there is no need to launch a browser window when sending or retrieving scores). Scores are sent as encrypted md5 strings which include a secret key visible only in the creator’s Linked account. There are versions available for Game Maker 6-8.
This is probably the easiest to use online highscore solution for Game Maker games that I have seen.