[TacticalCoder]

> by the big three

Which big three?

Gmail has something like 1.8 billion users. iCloud mail around 1 billion.

Microsoft with 400 million users of its email is closer to Yahoo! Mail (225 million users) than to the big two.

[AlotOfReading]

User numbers aren't the only factor. Microsoft has a much larger presence in commercial email than Apple. I suspect an outbound email from a personal provider is far more likely to be destined for an outlook inbox than one on iCloud.