That means that the same user that is member of multiple organisations gets paid for multiple times? We're doing a lot of consulting and thus we do have a lot of people from other companies that get to have a read-only peek at some of our repos - the price would increase at least tenfold for us.

That is really unfair to software houses that need to add customers to projects. We have 29 users and 51 outside collaborators, and 60 repos. You can see that this plan change is going to be unaffordable for us.

So to clarify: if I'm an organisation with 100 private repositories, and I add an outside collaborator with access to just one of them, I have to pay $9 a month for them?

I was quite excited about this change (we're an agency with a large number of repos and a relatively small number of users) until I read your comment.

Is there no distinction for "read-only collaborators"? We build software for many clients, they often request some (say 2 to 10) of their own users be added to the repository but only for viewing our work, not committing new code. If they are charged at the same rate as our own users the effective cost per repo for this model becomes $10-$50 per month!

This helps as a clarification. But doesn't help for usage. I was happy about the unlimited repos feature, and willing to pay the surplus. But if an outside collaborator with access to one repo out of 100s of ours must count towards headcount, that's a pretty useless model for us.