Buyerzone.com is a B2B website that specializes in helping businesses buy and sell a product or service. Registration is needed to sell and buy. You can subscribe to a newsletter, but other than that, there is not much use of CRM. Myplasticheart.com is a B2C website that specializes in designer toys and art. They offer surveys, polls, and even a discussion board for their members to participate in and become more involved. There are contests/giveaways that are run to encourage customers to make a purchase or return to their site.
Generally, these sites learn about my keyword searches and try to send me similar information. Also, the newsletter that they ask me to subscribe to inquires about my interests so they can send me relevant information that I may use, such as a sale, coupons, and such. As my interest change, so will the information being sent to me.