Trailing-edge users.

Trailing-edge users are those people we might otherwise make fun of, but they don't run adblockers and they don't constantly question the services they use. These people have used Yahoo Mail for a decade and will continue to for the rest of their lives.

5th most visited web property in the world(source : Similarweb). Mail, Flickr, Tumblr, Finance, Sports , Fantasy sports still used by a lot of users. I think it's a pretty sweet deal for verizon. you don't get a age old web property which everyone know off for this money.

Huge user base