1. An apparatus comprising: a content addressable memory (CAM) to store key entries corresponding to one or more classes of data represented by the CAM, each of said key entries being associated with one of a plurality of key tags, wherein each key tag corresponds to one of a plurality of subclasses of data; and logic to extract a data key from a data stream, to compare at least a portion of the data key with said key entries to determine if the data key matches any of the key entries, and to output one or more key tags associated with matching ones of the key entries to form at least a portion of a categorization vector to facilitate classification of the data stream.