Windows Mobile: "Mark All as Read" feature

Summary:
"...I personally find the "Mark All as Read" invaluable, especially
when dealing w/ tons of corporate mail or mailing lists... It should
install on Smartphone 2003+ and PPC WM5.0 devices..."

Details:
http://blogs.msdn.com/dennisq/archive/2006/08/29/730874.aspx

Note:
I put this on my Moto Q and it works perfectly. That said, your
experience may vary. Proceed at your own risk!