It also says that they were considering limiting invites per domain per day, which is quite a different thing than blocking all external invites, and it actually isn't all that different from what is done with email from domains that tend to send out a lot of spam.

However, the problems with this solution are a) that it doesn't discriminate between domains with a lot of traffic and domains with a lot of spammy traffic (though, again, that's just speculation and maybe they do have that data), and b) there's no message to the user that is being ignored. I don't know if jabber supports rejection messages, but it would be much better if they could get a message that let them know why they were being turned down so they could pressure their chat server operator to reign in the spam accounts.

It appears from the FSF post that they've actually tested invite requests, though, so presumably they are rejecting all invites, which makes the earlier email even less relevant as evidence of what is going on now. Surely the FSF has a contact at Google?