This is so sad. He's the first major performer to have died after I knew that the Muppets were puppets (I'm not counting Eren Ozker, who was only a major performer for one year, or Jerry Juhl, who hadn't been a performer since the 1960s).
I expect the next Sesame Street season premiere to be dedicated to his memory. I wonder how many currently unaired segments and epsiodes were recorded with his voice. I also wonder if the new "Elmo the Musical" segment will feature him as an announcer.
I wonder if the upcoming Muppet Christmas Carol blu-ray will be dedicated to his memory which would sort of be fitting considering the movie was dedicated to Jim and Richard).
Jerry Nelson will be missed. At least we've gotten interviews with him on Muppet Central, Tough Pigs, The Muppet Mindset, and The MuppetCast.