[kenshiro_o]

This looks very good. I have not delved into maths stuff for quite some time so it is refreshing to read such an approachable article.

Which other relatively simple techniques could we apply to find out who is similar to us in terms of movie taste, etc?

Also, It may be better to compute cosine similarity based on movie type, as it may provide less noise.

Moreover, I have never used R but it seems like a very neat language...