Running heel first is definitely easier in your typical modern training shoe with a giant heel lift. But when you put on a pair of lightweight shoes with minimal heel lift, mid-to-forefoot striking seems much more natural. Heel striking in racing flats is very awkward, and I certainly wouldn't consider it easier.
I definitely agree that moving away from heel striking can be very difficult after many years of doing it. I've slowly worked my way down from bulky trainers to lightweight trainers to minimal flats, and my achilles tendons gave me hell throughout the entire process.
I don't really have any intuition as to where the The Blues Brothers should lie on this type of map, so maybe you could explain why you think their placement is so ridiculous?
The similarity algorithm appears to be taken directly from last.fm, which uses some kind of collaborative filtering method on user listening stats to determine artist similarity.
In general, I think this map does a good job of grouping similar artists. Mapping a high dimensional similarity space down to two dimensions is undoubtedly going to result in a few data points that seem out of place, particularly when dealing with content like artist similarity where individual perceptions can vary drastically.
My first guess was that they used the artist.getSimilar API method. I dug around a little and found this:
"In April 2009, we crawled the website [last.fm] by starting with Beethoven, and the top 20 musicians most similar to Beethoven, provided that each has at least 100,000 listeners. We then found the top 20 most similar musicians to each of those with at least 100,000 listeners and proceed recursively. Our crawl yielded a graph with 2782 musicians, with edge weights the similarity between musicians."
- Emden Gansner, Yifan Hu, Stephen Kobourov and Chris Volinsky, Putting Recommendations on the Map - Visualizing Clusters and Relations: http://arxiv.org/abs/0906.5286
I definitely agree that moving away from heel striking can be very difficult after many years of doing it. I've slowly worked my way down from bulky trainers to lightweight trainers to minimal flats, and my achilles tendons gave me hell throughout the entire process.