24. The method of claim 23 , wherein the given keyword is further associated with a third feature present in a second segment of the multimedia content, and determining the relevance of said given keyword to the multimedia content comprises calculating the relevance of said given keyword to the multimedia content using, as inputs to the calculation, i) the relevance of said given keyword to the first segment of the multimedia content and ii) a relevance of said given keyword to the second segment of the multimedia content.
23. The method of claim 21 , further comprising determining a relevance of said given keyword to the multimedia content.