> Distance education is a common learning model in many large  
> university. The distances can be thousands of miles between teacher,  
> students, and email servers. For example, we have many students in  
> Japan who rely on communications from our LISTSERV in Philadelphia.  
> Those students are free to use our central email server, but from a  
> practical standpoint, they tend to use local providers.

That's a very good point. But again, unless you have a financial interest in
Goodmail, which your average local provider is just not going to have, there
is no reason to decide that only Goodmail-certified mail will make it to the
regular inbox, and the rest will go to junk folders. The smart and logical
thing to do is to offer certification from Goodmail or competing providers
as an option, not as the only way to reach people's inboxes. Besides, an ISP
in Japan is unlikely to consider Goodmail as an option, since Goodmail won't
even do business with companies not headquartered in the US or Canada.

Frankly, it is not a big deal to me if some companies want to spend money
buying themselves a guaranteed ticket past ISPs' spam filters. When you fly
there is first class, business class, economy, and most people are ok with
that. The problem is when you decide to shut down economy class in April and
business class in June, and your market position is such that, in practice,
a lot of people will be left out in the cold.
 
  Eric