How much illegal file sharing is still going on today? How much revenue is lost because of this?
It has dramatically changed the way the industry works, I don't think anyone can clearly say how much revenue has been lost but there are articles on the internet. I personally have noticed this to have caused a shift towards free download music and relying a lot more on stream revenue rather than album sales, especially for up and comers like me. I, mostly for this reason, have never exclusively sold any of my songs. Many of them are available for purchase on Itunes, beatport, etc., but I mainly promote a free download link which requires people to follow me on my soundcloud account to download the song, so I at least get something for the hundreds - thousands of hours I've put into making these songs!
Although I have even seen and heard of people illegally downloading songs that are available for free download for a social media follow.. so there's really no winning! =P
Soon I'm going to exclusively sell a song of mine for the first time so I'm really excited to see how many people download when its buy vs. free download.
Thanks for your question!