Vertical Integration

I'm reading Tom Evlinson (one of Isen's former AT&T buddies) about how consultants killed AT&T. (It is a great read if you have the time). I'd read how Consultants helped kill AT&T before, but this version is more personal. Evslin also gives lessons learned from AT&T, like about Vertical Integration versus Horizontal Integration. Vertical Integration is a monopoly idea about owning the whole network and selling retail. Horizontal means selling the same product to many markets, like Ice Cream.