..., I would have figured they could afford to pay 5ยข per mailbox per year (and MAPS might have even worked out a better rate than that for the big guys)..
http://www.mail-abuse.org/feestructure.html
Per year, for $1,000 users, cheapest option, standard pricing RBL+ $1,250 DUL $500 RSS $700 $2,450
or $2.40/per mailbox per year. Sorry my budget does not go there...
As I'm sure others will point out... RBL+ (which *includes* DUN and RSS) is $1250 *plus* $50/1000users per year. So it starts at $1300/yr/1000 users (or $1.30/yr, ie $0.11/month/user). It asymtotically approaches $50/yr/1000 users (ie when you reach Aleph-null users), or $0.05/year/user, or $0.004/month/user. Unless you only have a thousand users, I'd find it very surprising if anyone had problems fitting this into their business model. (My opinion here is academic; we don't have "mailboxes" - we're an NSP, no dial/DSL/cable.) Brian