How do sites get so many BizRate reviews without displaying a survey?

BizRate, Zappos

[BradUrani]

I've noticed that Zappos and many other stores have thousands of BizRate reviews that appear on Google Shopping, yet they don't actually display the BizRate survey on their checkout page. Is there another way they direct people to fill out a survey? It seems inconceivable that so many thousands of people would take the trouble of going to BizRate.com just to write a store review after buying something online.

[CPC_Andrew]

Yep - e-mail marketing. They give incentives to their customers to fill out a survey about their last order.

[MisterT]

Merchants with 1000's of reviews are usually pushing customers to review, one way or another.