I wonder if, should mastodon succeed, we'll see a gmail-ification.

Like, email was federated.
Then spam became a huge problem and so major ad-supported email providers blocked email from anyone sketchy-looking. Everyone flocked to major providers because they were free and had less spam. Increasingly, 99% of spam came from non-major providers so major providers understandably blocked most mail from small email hosts. Now most people use a major provider and email is only barely federated.