Fun fact: cosine similarity's first use in recommendation systems to recommend usenet groups.
(https://dl.acm.org/doi/epdf/10.1145/192844.192905 although they don't call it cosine similarity; they do compute a "correlation coefficient" between two people by adding together the products of scores each gave to a post)
(https://dl.acm.org/doi/epdf/10.1145/192844.192905 although they don't call it cosine similarity; they do compute a "correlation coefficient" between two people by adding together the products of scores each gave to a post)