Interesting...I should write a blog post about some techniques I've used that are similar to your example (modulo specific algorithms). Is there something specific you are trying to accomplish?
I would read it! I work with a specific kind of high(er) dimensional medical imaging data, and I think unsupervised learning could be used for classification and foreground separation. K-means is giving me some promising preliminary results, but I'd like to assign samples continuous probabilities rather than binary classifications. I'm relatively new to ML but trying to incorporate it into my research, so I apologize if any of that doesn't make sense!