Historically, we know that if we just pick top-selling items and e-mail them to people, conversion isn't that great. It's very hard to target in the pet space. You have to know a lot about that consumer.

It's just to let customers know that these are the items that other pet owners find useful.

People are really emotional about their pets and love to talk about them. We have a really intensive e-mail marketing program already. We thought it would be great to take some of the comments [from customers who are] having great success with products and get them into the hands of people who don't come to the Web site [often].

And, if it holds true as the number of reviews expand, that becomes more valuable.

One of our big concerns was negative reviews. We thought people would use this as a forum to bash items, and we wondered how we'd deal with vendors.

We were skeptical about whether an established brand like PETCO would see any conversion lift from HACKER SAFE but were amazed that it delivered such a strong increase in our conversion rate. HACKER SAFE has proven to be a very worthwhile investment for our online business.

They're just asking questions, using it as a forum to contact us.

The idea was to leverage customer involvement in the Web site and use it as a marketing tool. Most recent surveys say customers are very interested in what other online shoppers have to say. They trust the voice of other customers more than they trust the retailer or manufacturer.