I'll let Randi explain what went down:
It figures Granddad wouldn't be mad and tell all us kids to simmer down. ;-p
I see lots of problems here: DMCA is evil and must go, fair use must be properly protected, YouTube must find a better way to deal with DMCA violations (notify the poster, pull specific vids and/or give 24 hours to rectify the problem), and RIAA needs to calm the hell down (it's not like small snippets of low-quality music in an educational vid are hurting their sales).
Good to have them back.