[MlMt] Error?

[Bill Cole]

On 25 Mar 2014, at 19:49, Kee Hinckley wrote:

> On 25 Mar 2014, at 13:41, Benny Kjær Nielsen wrote:
>> You wouldn't happen to know why Yahoo rejects a message with a single 
>> URL? Is this some kind of spam-detection and if it is, why do they 
>> suggest adding text to the message (hmm, maybe this is a message 
>> intended for their web interface)?
>
> My recollection is that they are using it to block potential spam. 
> Adding more text to the message in addition to the URL will get it 
> past the filter. I think they've had that filter for ages.

That's it.

Most messages consisting of nothing (or almost nothing) but a single URL 
are spam, and in the past such spam was very common. It is much less 
common today (presumably a result of that pattern becoming widespread in 
spam filters) but it is still true that messages like that mostly have 
other strong spam-sign characteristics. Yahoo has had a problem for many 
years of poor maintenance of their unique mail infrastructure, and this 
is one of the externally visible indications: an archaic absolute 
rejection rule based on a message body pattern that uses a custom reply 
code. The state of the art in spam filtering was already moving beyond 
heuristic body patterns as absolute rejection criteria and custom 
extensions of the reply code space by 2000, but many mail systems have 
not kept up with that evolution and Yahoo is one of the most prominent 
examples. Giving away email service for free has a cost...