[...] 
 Of course, one would 
not find an HTTP GUI on the bigger networks dealt with on this list; 
only on the tiny networks.  So they're beginning learners and are, of 
course, welcome.  They will lean a lot, just as I did in the early days 
and do every day now days.
[...] 
scott
Let's see...
Google: Gmail
Microsoft: Hotmail/Outlook/Office365
Yahoo/VerizonMedia: Yahoo Mail
I'd have to say, there's some pretty big networks on this list that 
use HTTP GUIs for their email.
Of course, you might be big enough that you look down on the 
networks of Google, Microsoft, and VZM as "tiny networks" -- in 
which case, you're definitely entitled to your opinion, as all 8000
pound gorillas that look down on the puny 800 lb gorillas are.  ;)
Matt