For years, Benjamin Mako Hill has paid to host his own mail, as a measure to enhance his privacy and independence from big companies. But a bit of clever analysis of his stored mail reveals that despite this expense and effort, he is a Gmail user, because so many of his correspondents are Gmail users and store copies of his messages with Google. And thanks to an archaic US law, any message left on Gmail for more than six months can be requested by police without a warrant, as it is considered "abandoned."
Mako has posted the script he used to calculate how much of his correspondence ends up in Google's hands.
I host my own mail, too. I'm really looking forward to Mailpile, which should make this process a lot easier, and also make keeping all my mail encrypted simpler. Knowing that Google has a copy of my correspondence is a lot less worrisome if they can't read it (though it's still not an ideal situation).
The answer is surprisingly large. Despite the fact that I spend hundreds of dollars a year and hours of work to host my own email server, Google has about half of my personal email! Last year, Google delivered 57% of the emails in my inbox that I replied to. They have delivered more than a third of all the email I've replied to ever year since 2006 and more than half since 2010. On the upside, there is some indication that the proportion is going down. So far this year, only 51% of the emails I've replied to arrived from Google.
The numbers are higher than I imagined and reflect somewhat depressing news. They show how it's complicated to think about privacy and autonomy for communication between parties. I'm not sure what to do except encourage others to consider, in the wake of the Snowden revelations and everything else, whether you really want Google to have all your email. And half of mine.