[bizarref00l]

> - You must never send an email to someone with a Gmail address

You can be sending to gmail without knowing. Many business use gmail enterprise. I've been told that their EULA states no mining on private data, but that's very hard to believe.

[vollmond]

Even my personal email goes to a GApps account, grandfathered from when it was free for individuals.

[kedean]

And if they don't use Gmail enterprise, they probably use Office 365.