pg: what about allowing people to spend down their own karma to get an important post onto the front page? Sort of like Stackoverflow's bounty system. You could start with a 1:1 exchange rate and tweak it over time.
Ouch...points with no value already entice people to attempt to hoard and game the system to gain more. I don't want to think of what would happen if these points were suddenly given a tangible value.
