Today, Scott Allen released the full details on the survey on trust in online transactions:

Transactional Trust in Social Commerce
(PDF, 13 pages, 113K - Right-click and Save Link As or Save Target As to download)

it is a great survey (sponsored by Rapleaf) and gives a real insight into the impedements and catalyzers of buying and selling.

Key survey point is that ratings are the more important criteria for buyers and the seconf most for sellers:

Factors in determining trust
compared between buyers and sellers
Factor Buyer rank Seller rank
Posted ratings of the buyer 1 2
Reputation of the site or publication 2 3
Payment method you are using 3 1
Endorsements/testimonials 4 6
Intuition/gut-level reaction/prayer 5 4
E-mail or phone call with the buyer 6 5
Outside research of the buyer 7 8
Prior knowledge of the buyer 8 7
Personal appearance of the buyer 9 9

thanks Scott for putting this together.