mp3 market has the biggest potential for me.
Used to be that getting music recorded, manufactured, plugged and sold meant you were 100% dependent on about 12 layers of middlemen (some were vital because of the technology of the day, others were exploiting networking gaps)
Now, you can do every single part of the process for yourself. It's not going to be long before someone selling their music through their own website is going to have a massive hit that doesn't actually register on the "real" music charts, because they're outside the traditional circuit. That's what's so interesting about this, if a track has the right qualities to become popular, you can't hold back the tide.
The artist who does this first will be the first to ever make more than single digit % of the profits from their own music.
any record can become huge with proper marketing. There are several charts other than billboard that are just as important. The majority of artist make most of their money from touring and merch sales. Unfortunately record sales will never be what they were. A bitcoin based concert ticket option would be amazing. Ticketmaster prices are outrageous.