It's obviously a hoax or something. If he really wanted to "add you to his address book," he'd just examine your profile on the forum and add your e-mail address listing to his contact list. And he says, "In the future I will be able to see any changes in your contact details." I highly doubt you can see contact detail changes from standard e-mail. Don't reply to that message, it probably... well, I don't know.
About the strange site, I did a little examination and discovered that George, as appears to be his name, is actually using a 50megs account. I thought that the "5u" thing was a little familiar, so I went to 50m and found out. Anyhow, I tried typing in
http://euchel.5u.com/cgi-bin/fm
since that's the file managing thinger in most 50megs account systems, and - please keep this a secret - I found out what the password was. Anyhow, I just took a little look at what's in that directory.
>>I could guess that the pages were slapped up there for no other purpose than to fill space and make the webhost think things are afoot, while the space is used purely for personal filehosting behind the scenes.
I don't really feel guilty about peeking in there, because if it's a filehosting site, someone would probably see the files anyway when whoever would show them off. But when I took a look in there, all that was in there was the page, a "page2," and some other file.
Since I now think that it's possible this is some kind of joke, I have another idea. Let's go with the e-mail thing (get a[nother] free e-mail account from some place like Yahoo so we're protected in case of spam, and send him a bunch of e-mails. If, by chance, he gets them, he might be so overwhelmed by so many messages that he might give up and let out the secrets of why this crazy site is on there.