Do you do any marketing with it at all or do you just seat back and wait for them to find you?
I have some experience with ODesk, which is another internet based services matchmaker.
Some ODesk people make a living from it. But they market themselves aggressively within the service by keeping their profiles up to date.
The coin of the realm on all of these online bidding sites is your reputation score on the site. This is because on all such services there are too many members who belong who have no reputation, IE, no completed jobs and no client references within the service. Another way of saying this is that everyone starts there at 0 and most buyers will look for someone with non zero feedback.
IMO, you
must bid
plenty of low rate projects in order to gain a few paid projects that then can give you "non empty" feedback.
Every such service is glutted with third world people with very poor English and bad skills who are quite willing to present themselves as geniuses in 15 languages. Virtually all the offshore people on these sites lie, so there is a huge unnatural inflation of provider's supposed abilities. You pretty much have to lie and exaggerate in order to stand out.
Lastly, on online services every buyer is looking for a bargain. You won't find quality clients on these sites. You run into lots of impatient and flighty dumbasses with no real needs.
A guy I ran into from Odesk who did some work for one of my past clients asserted to me that he grossed about $60K/yr and had gotten his rate up around $30.
IMO most these services are a waste of time if you need real income. And no, I wouldn't pay anything for a premium account. I've read some stories about making a go of it. Most people who do, like I said, have to dedicate a lot of effort to creating an initial reputation score.
If I remember some stories I will post the URLs here.