I've implimented a high score system in my browser game, Driftwurld! I think it works!? It updates once per half hour. I'll be posting a rough tutorial with the code for a high score table in awhile.
It also has a system where it only shows the first two letters of names not checked out yet. I really quite hate it when games go to all the effort of having nice graphics and depictions, only to let players have crappy names (ie, not a jot of connection to the fiction, or any fiction for that matter) and display them everywhere. I'm checking them manually in the DB at the moment.
I'm wondering whether to make it that when you log in it takes you to the high scores then you click to homebase, so as to emphasise high scores, or just keep high scores as a button on the homebase screen?
Also implimented the ability to gain these scores (power factor) by only three per hour, so far (ie you play for five minutes, get the points, but then it'll be an hour before you can do so again). You get one point at the end of each paragraph of the story completed.
Latter I'll add a lords system that uses the power factor to determine who is promoted to one of the limited number of lord positions for a month!