Re: [exim-dev] RCPT TO verification

On Thu, 2010-01-07 at 09:39 -0500, Richard Welty wrote:
> as far as i know, most major ISPs who tried callouts found them
> unworkable and stopped using them.
>
> Verizon in the US was a prominent example. tried, stuck with it for a
> while, eventually gave up.

...because they could no longer handle the volume of complaints and the
number of times other small, medium and large operators had blacklisted
them for causing resource exhaustion. That, and the attendant fact that
they started to lose business and get legal threats from customers.

The bigger the system, the more noise the complainants make. It's only
sustainable to a point.

Graeme