[joelmoss]

The reason is that Github does not always pass on your email to us, and we need to be able to contact you. Also, your Github username is not always available on our system, so you have to verify or choose a different one, as someone else may already be using it on our system.

[cessor]

Thank you for your clarification. Yet I wish more app creators would understand how I feel about these things (others might think so too):

You don't ever need to contact me unless it is for confirming accounts, which you don't have to, because I just oauth-handled you one. Username collisions could be handled by suggesting mangled or decorated names but aren't really the issue here. I am way more concerned about my email address.

It is not to be treated as a commodity and I hate the follow-up emails that I immediately receive, each and every one of them.

I understand the concerns that cause this behavior and believe it can be quite hard on today's market, so "hooking" in users by getting their email address might seem necessary. Yet I feel strongly about the whole thing. I don't want to give out email addresses and oauth is an appropriate way of handling identity and access. Not only is asking for an address redundant but it's encroaching. Maybe without this barrier you could improve the bounce rate.