In this forum, you will find alot more deals on mileage runs in general, than you will find mistake fares.

MRs are like SEA-LON for $300 all inclusive (found, bought and flown twice in March 2004 or 2005); whereas one might consider as an example of a mistake fare SEA-ART for $37 all inclusive (summer 2005).

Either way, as with any bulletin board, one must spend some time to get a flavor of what and how to search the threads.