The scores are not stupidly high. They are achieveable within the context of the game itself.
There are:
Member of the Month
100 posts of the Week
Happy Hour
Posting comps (although these are rare now).
There is no evidence to suggest that these advertising/competitions have provided any incentive to get people to post extra... apart from the people that already post to begin with. The same principle applies with the arcade and it would be stupid to reset it completely, never mind reset it every 3 months. "Oh don't bother trying to get any score at all on there, it'll be gone soon"
Surely it might actually create more competition if the forum actively encourages people to beat somebody, especially if that person is somebody people aren't too fond of. "That Mike is a *****, the person who beats him or gets the closest in the month of January wins []" same comp without the stupid reset. Lewis and I have an ongoing rivalry over the game Ping Pong II because we were competing with each other for the best score. You only need to look at the first couple of pages in the hiscores of that game to show that this approach does generate more activity.
You never use the arcade because you have no interest in it to begin with.













