[Jeff_Brown]

Is there no danger of collusion among reviewers?

Can negative reviews come back to haunt the reviewer? Or are users only asked for positive reviews (i.e. silence being the most negative review possible)?

[amitsy]

Yes, there is that danger but we have not seen that happening as of yet.

Users are only asked for positive reviews

[beachy]

If you are successful, then next I suggest you will be following in the steps of vendors offering online reference checks, e.g xref, checkster.

You will need all sorts of fraud detection, e.g multiple reviewers all coming from the same ip, and your customers will pay for that security.