From Defamer:

Comparisons To Barbra Streisand Drive Nellie McKay To 
Nervous Breakdown

A truly gifted singer/songwriter usually can convey emotion and
inner life through a few simple chords and some heartfelt vocals. 
Sometimes, however, it requires a little more. A reader sends in 
this report from last night's Nellie McKay performance:
Nellie McKay had a great show at the Troubadour [last night], 
but had a minor.actually, pretty severe on-stage meltdown near 
the beginning:

"She was talking to the audience about the problems she's been 
having with Sony and someone shouted "Shut up and sing!" This 
seemed to touch a nerve with dear Nellie. After politely explaining 
to the miscreant that "If this continues with Sony, I will leave the 
music business, BITCH. And NEVER SING AGAIN," she started 
screaming and crying and "They say I'm just pulling a Barbra 
Streisand," and "You have NO IDEA WHAT I'M GOING 
THROUGH," and corporations are raping the world, etc. etc. As 
the audience, who had previously been laughing and hawing at
everything she said, stood there in uncomfortable silence."

http://www.defamer.com/
(photo of Nellie here too)