[caw]

It's not that you can't expand with #3, it's just more difficult.

A friend of mine runs onlyattech.net. It was initially launched for Georgia Tech students, and then when it came to expand, they became the "Only At network" and got onlyatuga.net and onlyatuf.net

Of course, in the taxi example who's to say that BestBostonTaxis isn't already taken? You'll end up spending a lot to keep your branding and moving into a new network.