First, Keith is a great guy. Second, he is smart, very smart, and very accomplished (read his bio here). Good move by Cisco. Keith will have an ongoing senior strategic role within the company.
Although ExtendMedia plays in the enterprise video management space, I have never considered the company to be a direct competitor to Sorenson Media. Extend's primary customers are major cable companies, among others, and its technology powers IPTV solutions.
Sorenson' raison d'etre, on the other hand, is to provide the highest quality differentiated encoding solutions to businesses of all size.