Fingerprint - Email Client Usage Statistics
“There has been no way to get accurate, up-to-date statistics on email client usage. Until now. Fingerprint shows you which email clients your readers are using.”
Fingerprint is a new app from the guys behind Litmus based here in Edinburgh. The stat tracking is done by inserting a line of HTML code into the email mail out and returns you with email client usage data. Pretty simple but looks great.