Microsoft might, I suppose, have a policy against microsoft.com accounts on other firms infrastructure, and therefore if it needs a Google account uses gmail or other non-microsoft.com domains.

They have already failed this test: they are already publishing extensions using [email protected] and [email protected], doubtless many others!

I believe Google requires you publish Chrome extensions with an @gmail address, in which case MS doesn’t really have a choice.

Absolutely untrue, as mentioned elsewhere in the thread. I have Chrome extensions published under a non-gmail email address.

Any idea what problem Google is solving by requiring the use of gmail?

Naivety on the internet, and people believing what they read on a web page without checking.

Google doesn't require a gmail adresse to publish.

Yeah, I didn't think it made sense.

Good grief--that is so evil (not to mention anticompetitive) that I didn't even consider it!

Not sure what would make using a Gmail account anticompetitive, but it's also not true. You need a chrome web store account (which they amusingly encourage you not to use your personal email for) which can use any email address.