Youngmoo Kim had asked everyone on the ISMIR recommendation panel to briefly summarize what they think will happen in the next 5 years of music recommendation. However, it's really hard to do so in less than 4 minutes.
From my perspective the most interesting development in the next 5 years will be the increase in the amount of data we will be working with. We will have a lot more of the same and we will have additional sources. Combining different sources is an interesting challenge, but the main challenge will be to scale things up.
All of this additional information will lead to much better recommendations overall, and in particular in the long tail. We'll be able to detect new trends such as an up-and-coming artists or the emergence of a new subgenre much sooner. We'll be able to localize recommendations a lot more.
At the same time there'll obviously be a lot more music to choose from. I'd roughly estimate about 200 million tracks in Last.fm's recommendation engine in the next 5 years. That's more than 1000 years of continuous listening. Subcultures and genres will emerge faster.
In 5 years recommendation engines will have a much better understanding of listeners. While Last.fm, Pandora, and others already do a lot to understand what listeners are interested in, I'm sure there is room for a lot more improvements.
Another interesting development I'm looking forward to is data portability and openness. In particular, I'm looking forward to users being able to move freely with their personal data from one site to another. Similar to how Last.fm users can already today allow other sites to access their data.
I'm also expecting to see a lot more artists and labels embrace recommendation engines. Similar to SEO (search engine optimization) more artist and labels will try to do a lot more REO (recommendation engine optimization).
Obviously mobile applications will be very important, and so will mobile music recommendations. And I have no doubts that human-to-human recommendations (which are strongly supported by Last.fm) will continue to be very important, maybe even more than they are today.
I believe it was Brian Whitman who said that recommendations will be a commodity. Every music site will have recommendations. Just like almost every web 2.0 site out there supports tagging. I believe Etienne Handman made a similar point when he previously explained to me why he expects the word "personalization" to fade away. Everything will be personalized, it will be the default option.