See how Build.com allows customers to sign up for their Deal Of The Day which is powered by MyAlerts. Sign up on this page to see how it works.
World Markets allows consumers to sign up for Price Alerts on any product on their site. This has NO decrease in same day visitor/purchase conversions, but helps them pull forward all of the interest in any product for when it goes on sale, helping reduce margin erosion dramatically. See it here.
Target allows gift givers to track wedding, baby, or graduate registries for changes to any registry. New products added, price alerts, or back in stock alerts. This helps drive more return visits to any registry, moves revenue forward, and is a huge feature benefit to registry creators which increases products added to any registry. See it here (follow this registry)