Admin...
Why not give a financial incentive for courier companies to post work on mtvan, and for ODs to find work on it?
Credit could be given off the next month's membership, or SMS credit... say, £1 per job accepted - 50p to the poster and 50p for the driver.
You couldn't just give credit for work posted, because then anyone could post non-existent jobs just to get money off. You'd have to give the credit off work which is actually accepted through the website.
I reckon the extra jobs would be worth more to the website in new membership fees than what it would cost.
...and anyone who submits a really good idea should get free lifetime membership... ;)