Well, we wondered if we could use this data to say anything about the spending habits of email addresses by domain. For example, do AOL users spend more than Gmail users?
They managed to deal with the vast array of global campaigns and currencies to establish if user A spent more than user B. Once they had aggregated this data they looked at the email extensions of the winners. It turns out that Hotmail and AOL users tend to spend the most.
As you can see from the graph above (read top to bottom), Hotmail users spend 6.4% more than Yahoo users and 3.7% more than those with a Gmail address.
Their assumption is that Hotmail/AOL users tend to be older, so have more disposable income. Young people today are more likely to sign up to a Gmail account. It presents an interesting case for email list segmentation though, knowing this set represent your larger spenders.
Have you run any email tests along these lines? Feel free to comment below.