Having dealt with EarthLink and other CLEC's who advertise large fiber routes, but who in fact do not know where they are nor do they want to sell transport on them for some weird reason, Lit Buildings are an interesting thing.
Cable companies and ILEC's don't offer information about how many buildings are lit with fiber. (It mighthttp://www.blogger.com/img/blank.gif be because the number grows every day.) CLEC's do with twt is in the lead with almost 15,000 buildings on-net. L3 is next with 13K. Optimum Lightpath has 5000 and Zayo - now combined with AboveNet - has 7900.
On one side, as a service provider, if you partner with a carrier - cableco, ILEC, CLEC - you should be leveraging their lit buildings for your own sales.
It should be easy to offer backup circuits and redundant Internet pipes in a lit building. Internet is so pervasive these days, especially with companies going all in to the Cloud.
Install intervals for fat pipe are faster in lit buildings. No six month build period.
Incremental sales in the same building means that you sell a fat pipe to one customer, who basically finances for you to light a building. Then you sell smaller pipes to others in the same building! That's called getting deep. A key concept in my book, Lit Buildings, a step-by-step sales guide.
The flip side of the Lit Building is that you want to get as many buildings lit with your services as possible too. It expands your service area - or better yet deepens your service area.
If you are utilizing assets of other carriers, if your sales strategy gets you deep into a couple of buildings on the same side of the street within a mile of each other, you can build your own fiber to them. Then these customers become really profitable!
Sell Deep and Sell Lit (if you can).
BTW, this works for Wireless as well. Once you have gear on a building, it is Lit. You need to sell as deep as possible into that tenant list.