14. The method of claim 13 , wherein identifying the second set of features that is a match to the first set of features comprises determining that the second set of features is a match to the first set of features.
14. The method of claim 13 , wherein identifying the second set of features that is a match to the first set of features comprises determining that the second set of features is a match to the first set of features. 15. The method of claim 14 , wherein determining that the second set of features is a match to the first set of features comprises: with a statistical model that applies different weights to different features, generating a score indicating a similarity of the first set and the second set; and determining whether the first set is a match to the second set based on the score.