At 11:11 8/15/2005 Monday, Hal Keen wrote:

[...]

>I have lists where unnecessarily losing subscribers is a Very Bad Idea, so I
>generally wind up contacting the subscribers directly and maybe working with
>their email people to get my domain whitelisted. (If I can't reach the
>subscribers, it's an indication the addresses have really gone bad.) More
>Draconian approaches (NOMAIL or simply deleting the problem subscriptions)
>are possible, depending on the importance--at your end--of maintaining
>contact with your subscribers.

Hal has hit a nail on the head -- this is one of those "value adds" that a list-owner can provide -- getting involved in the problem source identification and resolution of "email" problems.  Often, they go beyond the list itself, and are institutional/ISP parameterization or design problems e.g., mail rejected because it discusses a "bad" word, as opposed to being that "bad" word such as p o r n.

You may enjoy reading this 

http://www.emoderators.com/moderators/how2list.html