[Theodores]

You should also get some information about the computer through on the email. If someone is on IE8 with an 800x600 monitor then they are a different class of customer to someone running - say - Chrome on Linux. Knowing someone is 'a Mac user' is also a telling signal if you intend to sell them something.

Also time on site is useful to know. Did they read the page? Maybe if they spent a good few minutes with the page open.

IP address - GeoIP to city with country - is also a useful thing to know. Do you really want to respond to that guy where shipping prices mean that a sale is effectively unrealistic?

Such mild-deep-stalking would be helpful to your customers and make your service appeal to a wider audience.