[Greylist-users] Microsoft and Greylisting

[Sam Kalet]

> Anyway, Microsoft's 'Penny Black' seems to me it has very little 
> in common with greylisting: it's strange to say it's about 
> "delaying", it seems much closer to the "email tax" proposals, 
> paid in CPU cycles so no need to also solve the "micropayments"
> problem at the same time.

I have also seen this idea of slowing transmission of spam by some sort of
traffic shaping at www.spamsquelcher.com.  Too bad it is priced so unreasonably
high or I might consider it.  I haven't come across an open source
implementation of this type of approach.