#!/bin/sh
( echo host.do.main runs `/bin/uname -s -r`
) | /bin/mail linux-version@nvg.ntnu.no
I suggest that you run the script out of cron, at 3am every night. If you prefer to you may run it less often, but a one-line e-mail message doesn't cost the earth and new kernel patches come out almost every day sometimes.
The addresses of the machines or contributors will not be published, only how many run each kernel revision.