How exactly does one purchase their solution? Or more exactly what is being purchased? Do you place your servers on their rack in various data centers, and then have access to their backbone at cheap rates?
Or if you're a colo/dedicated server company you can use them as an upstream. They also sell layer 2 transport services (built over MPLS) between any two of their POPs, for ISPs that want to establish a new POP somewhere and get 10 or 100Gbps connectivity between them.
You buy transit at any "on net" site they are at, and that can include static IP routing with IPs they lease you or you use BGP to announce your own IPs (from the correct regional RIR). This is "The Internet".
> Regional Regional Internet Registry
:P