David, Paul and I have just finished launching our latest product, Fingerprint!

From the Fingerprint home page:

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.

Knowing which email clients are popular means you can be certain your messages are being displayed as you intended. Get actionable statistics within 24 hours of sending your next campaign.

Fingerprint is a clean, simple idea, and the data we've received so far (on our own mailing lists) is proving incredibly valuable; we had no idea 6% of our subscribers read our emails on an iPhone!

How does it work?
We give you a small 'bug' to put in your email, it's a small bit of HTML that we use to track which clients your subscribers are using. Every 30 minutes we update your analysis with the latest stats from your readers. The site offers percentages, and there's a spreadsheet you can download with a full breakdown of clients and quantities.

How much does it cost?
We're charging just $39 per analysis. An analysis is a two week snapshot of your subscribers' email client usage.

Why should I care?
Good question. It's very hard to know which clients to design your html email newsletter for, and with clients such as Lotus Notes 6-8 and Outlook 2007 out there, it's often unrealistic to design for all of them. Especially since there's a growing number of smaller, web-based clients. Do you know how many of your readers are using these?

Fingerprint gives you a single report answering all these questions, and allows you to make a firm, informed decision on which clients to design for and support.

From the data we've seen passing through so far, you'll be amazed at the results. During development, Paul, David and I had talked about what sort of results to expect, Outlook would be high, naturally, we also expected Gmail, Yahoo, AOL and Hotmail/Live mail to be up there. So far only Outlook has proved as popular as we expected, the iPhone was a notable surprise for our own list, with Lotus Notes making an unexpected appearance as well.

I can't wait to see the overall averages per industry!