To paraphrase Dostoyevski "All dancers do swing outs alike, but every dancer is silly in his or her own way." Silly moves add a little personality to Lindy.
The point is to do unusual and fun things, while keeping the rhythm of the music.
Ealry lindy was very silly: consider the dance sequence from Hellzapoppin.
Silly moves include:
wikipedia.org dumped 2003-03-17 with terodump