I've never heard of them. but i googled mp4nation and it looks like they are on a forum. Here is their most recent post:
http://forums.dealofday.com/showthre...899#post936899
I'm assuming the person posting is the same as the one who has the website because they are linking to mp4nation.com
if they won't respond to email, maybe it will be different in a public forum.
i googled "mp4nation" without the quotes. i tried putting in the link but it didn't work so you'll have to google it yourself.
hope this helps.