I find QT helps more than hurts. Reading the success stories, hearing about other writers' progress, etc is all motivating. I'm crazy disciplined though - once I start writing, if I tell myself I have to finish a scene or so many words or whatever b/f I can be online, I obey myself.
It's a community of support. Especially if you're a) socially challenged and most writers are (except for me 'cause I'm hip and stuff) 
or b) your spouse/parent/besty/house cat doesn't get/understand/approve of your writing. QT helps me on those days when I say, "f*** it, I'm never getting published, let me get cracking on grad school."
