That would be the cosine metric then. I don't think it is that simple. The position (or dimension if you will) of a keyword in the data-vector is all important.

That would be the cosine metric then. I don't think it is that simple. The position (or dimension if you will) of a keyword in the data-vector is all important. So equal vectors in terms of the symbolic presence of a number of keywords will generate great cosine distances the moment the keywords are not in equal position.