Does anyone understand the recent FCC "Spectrum Auction" that sold TV spectrum to wireless providers (so that over-the-air spectrum currently carrying TV signals will be devoted to broadband instead)?

https://www.fcc.gov/consumers/guides/consumer-faqs-tv-spectrum-auction

The auction was held at the end of March/early April:

http://transition.fcc.gov/Daily_Releases/Daily_Business/2017/db0413/DA-17-314A2.pdf

It looks like in some markets, over the next three years or so some stations will stop broadcasting, while others will start sharing channels with other stations.

My question, I guess is: if a station with two subchannels starts to share a channel with another station with two subchannels, will it still have room to carry all of those subchannels? Or will some subchannels be closing down?

It's pretty complicated and each market will be different, but with less spectrum left for broadcast stations overall, there will be less real estate for digital networks. This will most likely result in some of the less profitable networks going out of business. There is also a new broadcast standard called ATSC 3.0 being implemented in the next three years, which could create more opportunities for subchannels. But nobody really knows what will happen since the new standard isn't going to be mandatory, but at the same time will require consumers to buy new equipment (much like the digital converter boxes from 2009). Personally, I think its going to turn into a real mess.

sounds like it'll be one gigantic mess and leave a LOOOOT of people confused!