Yahoo and their mail filters..

Fri Feb 27 01:08:27 UTC 2009

Brian Keefer wrote:

> The other options is to stuff all the spam messages in a folder and
> expose them to the user, taking up a huge amount of storage space for
> something the vast majority of users are never going to look at any way.

Which is, in fact, what Yahoo! does by default.  Users have the option to 
have that stuff deleted immediately, should they desire.

> Blocking an entire site just because one John Doe user clicked a button
> they don't even understand just does not make sense.

You're right -- but Yahoo! has a sufficiently large userbase that they can 
count multiple complaints before blocking anything.  Same story with AOL, 
and Hotmail, and Cloudmark, and many others who've used this technique for 
years.

In all of those cases, they have safeguards to prevent gaming, to prevent 
bouncing, and pretty much everything else anyone's suggested thus far in 
this thread.

> Last, anywhere that I've seen extensive use of forwards has had a maze
> of difficult to untangle abuse problems related to forwarded spam. Any
> site allowing forwarding should apply very robust filtering of outbound
> mail.

Very true.  MAAWG published a document last year which includes some 
additional recommendations:

http://www.maawg.org/about/publishedDocuments/MAAWG_Email_Forwarding_BP.pdf

-- 
J.D. Falk
Return Path Inc
http://www.returnpath.net/