Personal recommendation is the best form of advertising.
Another advantage that greedbay had (and one they've now thrown away) was the ability to judge if a buyer or seller had a good reputation via feedback.
I think ebid is gaining ground not because of any adverts but because people are sick to death of greedbay for so many reasons that they are looking for alternatives,any name or web site address they hear of, they then check out to see if they can use that site instead.
Hopefully with more and more listings going on they'll be able to find what they are looking for on Ebid,at a good price and delivered on time,then they too might pass on the message.