This only presumes that you have line-of-sight or uncanny luck to have a reliable Fresnel zone to bounce signal through---but this is still constrained by distance. I used a "Portland, ME to Portland, OR" example to emphasize that these links aren't the kind that you can use allocated low-power radio spectrum to connect as in WiFi. You may be able to max out your upstream capability with local radio, but you can't supply bits to the other side of the city, state, or country. Unless everyone has the same exact interests as you, you won't even have the bits they want---this is what the pub-sub mechanism has to address on top of the content-network. Some people will specialize in carrying the bits that everyone wants and at every step of the way, nodes will have to look at subscription demand and throughput to decided which bits are sent in a batch. Yes, we can imagine our wireless routers as a low-rate signal system with focused high-rate beams, etc, but the probability that you will reach an interested audience from your radio is low. This is why FM/AM radio licenses are so valuable, and this is why having a content channel carried by all the regional cable monopolies is so valuable and vulnerable to censorship---there are many people who would love to watch Current.tv or Al Jazeera but cannot get it in their own regional cable systems. However, radio and cable are still synchronous mediums, which I'm suggesting we should back away from.

Using radio always assumes that there are other nodes interested in what you're sending. In nearly every case of radio-based Internet Service Providers I've been able to find, users always find that the service is "great" for the first month and thereafter totally sucks in every imaginable way: slow speeds, down-time, and bandwidth caps. There's only one tower and enough bandwidth for so many users, after that, there is no upgrade path because almost all the spectrum is allocated. This is guaranteed to happen for any homebrew WiFi network or municipal WiFi network---remember that you only get three separate frequencies without overlap ( http://www.bridgingthelayers.org/channel_overlap.html ) The limits are obvious with FM and AM radio is regulated by the FCC to prevent channel interference between cities---you never get "new" stations, you only get "different" stations when a broadcaster changes format. My favorite example of a broadcaster changing "format" is WHFS in Baltimore, MD---one day it was a progressive rock-radio station and the next morning a spanish-pop-radio station, without warning. (The DJs working there had no idea this change was coming.) By redefining the network medium to "bits via matter" instead of "bits via energy" (SD cards in my example), and relaxing our attention-spans to something less than "instant", you get more bandwidth by adding more cards to the network as needed. We may be getting better at using radio spectrum, but it will always have a political limitation of how it is used when it has real reach to many people---in short, if you can touch many people via a medium, more than a few people will always seek to control that access for their own interests. Bandwidth for information transmission via energy I still believe is scarce and will always be scarce for any situation where you wish to send to many people over long distances. The medium has to be redefined away from energy to matter---and perhaps, just to throw a huge monkey wrench into the mix and stir the pot more---this is what newspapers (which in their print format are already sending matter instead of energy to your household) need to add to their offerings to save themselves. Now, imagine receiving a 4GB SD card with your morning newspaper every morning while the paper-person retrieves old cards during delivery---and what would happen if you were uploading back to everyone else on those same cards? 8GB/day in and out becomes 56GB/week becomes 2.8T/year of data transfer, one SD card at a time. Relaxing our need for synchrony could make newspaper profitable again.

Subscribe to two newspapers and you double your network bandwidth and no one needed to climb on a roof. :)