Own your identity by Marco Arment:
If you care about your online presence, you must own it. I do, and that’s why my email address has always been at my own domain, not the domain of any employer or webmail service.
…
Sadly, most people don’t care about giving control of their online identity to current or future advertising companies.
But there will always be the open web for the geeks, the misfits, the eccentrics, the control freaks, and any other term we can think of to proudly express our healthy skepticism of giving up too much control over what really should be ours.
I am reminded of that old thing: “if you do not pay for a service on the web then you are not a customer, but rather your content is a product that is sold to advertisers”.