Does anyone have any idea what program he's using for this?
I would suspect that it's because he feels browsing web pages doesn't need to be instant, in a lot of cases, and he can just fetch pages via email and read them later at his leisure, and also have a convenient archive of them.
Assuming nothing changed in last 3 years, there's a simple script on gnu server that does the trick: you send an email with subject "wget http://websi.te, and get response like this:
I would suspect that it's because he feels browsing web pages doesn't need to be instant, in a lot of cases, and he can just fetch pages via email and read them later at his leisure, and also have a convenient archive of them.