Product/Item User Reviews

In another thread, a user said that the search engines really favor sites with frequently changing or fresh content.  Most major ecommerce sites have item reviews and I assume that it is mostly there to get more dynamic content that they don't have to create.  Many of them even allow reviews that trash the product that they are selling (as I recently noticed at a Sears item).

Anyhow, has anyone attempted to do this with CUSTOM fields?  Could it be done with a custom fields? 

If NetSuite adds a "product review feature", it would also need an automated way to send out a request for a product review to each customer who recently made a purchase.  I recently receive a request for a product review after making a purchase and I think that is the only way to get any level of participation.  It would also need a feature to allow old reviews to expire and maybe a way for other customers and the administrator to rank the quality of each review...then the more informative reviews show up first on the list.