I was responding to the part of OP's comment that alleges that Gmail is only big for personal email, and there's not a lot of that being sent. Gmail is clearly

I was responding to the part of OP's comment that alleges that Gmail is only big for personal email, and there's not a lot of that being sent. Gmail is clearly massive for enterprise email. I'm also not sure why this wouldn't correspond to market share in number of emails sent. All of those enterprises using Gmail are sending tons of emails internally.