They really get into sematics with this topic - a "performance" can and usually does include lip synciing with the usual excuse " XXX has a lot of complicated dance moves and it's hard to sing and twirl so he/she twirls. It's a performance of the song..."
a live performance also falls into this catagory. You need to look for or hear the words "singing live..."
I like Ashlee a lot (I would argue with the fuzz that she rocks - Cortney Love rocks - Ashlee is a santized Cortney in the vein of Avril Levine..thinks she's all rock then poses on 17 magazine with N'Sync :lol ...) Rock is still hard drinkin, hard durgs, wacking people on the head with guitars and showing your boobs in pictures with fans..