Just a couple of corrections to two of the posts in this thread:
>I simply have some problems
with /this/ current incarnation of a best practice, and I was querying whether
it had applicability outside of the SORBS/Trend Micro world.
I think you are mixing/confusing SORBS and MAPS. MAPS was bought by Trend and is run as a service based on subscription fees. SORBS is whatever it is. If you don't like SORBS, that's great, but don't tar Trend with that brush.
>2) Your reply to Dave's post is not useful. It's not even useful if >you consider it pure hyperbole for effect. There are many ways to >reduce spam, the "single most effective" does not stop even 50%.
Actually, that's not true. I don't want to get into an argument about "single most effective," but I can guarantee that using a good reputation service will block more than 50% of the incoming spam to your network. The leading ones normally hit the 80% range.
In fact, many of the popular anti-spam appliances are completely miserable at the content filter end which is applied post-reputation service; without reputation filtering, they wouldn't be worth using.
(My information is based on monthly testing of anti-spam appliances we have conducted for the past 5 years. For example, this month we are looking at 43 different appliances and 25 reputation sevices)