Dogs and things wrote:But what's the problem with people (rather: people-like entities) abusing Gmail for spamming practices if some good anti-spam feature makes it impossible for the baddies to register on one's board?
I agree

and I use several measures myself. But...
drathbun wrote:As a board owner, it's quite easy to say "bah, ban gmail and 70% of my spam problems go away" isn't it?
hotmail, yahoo, gmail... any free email account is subject to abuse. Spammers are using the fact that board owners are, as you are, reluctant to ban gmail outright because it does have so many legitimate users.
Why do people spam? is it because they have nothing better to do? No, it's because they think they will make money. Free email accounts are easy to create, cost nothing, and therefore the spammers find them quite useful. They don't add any costs to the process. To be clear I haven't blocked gmail myself. I wanted to, but my board members would not let me.

There are several compelling reasons why someone would want to use gmail (or some other service) that I can't ignore. All I am saying is that blocking gmail is an option that can be considered, and given the statistics I've collected it would be quite effective at blocking spam registrations.