Digital goods are vulnerable to piracy and copy.
Unless someone solve the piracy issues, the market will not be able to support the artist and author.
The corporate model of content distribution (eg., iTunes) relies on control and force of law to prevent people from using alternative pipelines. This approach has had some success, but it comes with high negative social costs (to maximize profits, greater control over the networks will be exercised - i.e, Net Neutrality Lost Cause - the result is greater and greater wealth concentration - one might correctly assert that millions are driven into poverty as a result).
There are alternative models that allow content to be freely distributed while still providing income to the artists and authors.
As a case in point, I've been working on a system that issues records of a digital work into the blockchain and allows those records to be exchanged. That digital content can thus be considered 'unique' and collectible.
See
http://rarebit.github.io/project (you can use testnet to play around with the web client without spending actual bitcoins)
The record is like a stock certificate that could potentially increase in value if the content originator becomes celebrated (it's not unusual to see works by living artists selling for millions apiece).
A photographer on flickr, for example, might issue limited editions of a few photographs and allow fans to buy them. The sale might include legal rights, like allowing the purchaser to print the file and exhibit it in a public place, or resell that physical print alongside the blockchain record that authenticates it.
For an unknown artist just starting out, the tokens might be worthless at first, and people might pay for them simply because they want to support work they think is worthwile (like receiving a thank you gift for a donation).
Another use case might be a musician that issues a special 'collectors edition' MP3 (perhaps limited to 1000 copies).
An author might perform an online book signing (and still remain anonymous if the content is seditious).
Yet another use case might be signing autographs for people who show up on a twitter account at a specific time (if this were done randomly it might help encourage people to visit the page more often - these sorts of manipulations I hereby denounce). In this case just the digital signature would be recorded and traded.