As far as info in your bio, I vote for short and either witty or just to the point. One sentence. Maybe a second one that relates to the specific article at hand. I googled myself once and found some website had dissected point by point my bio on my employer's page and, although it wasn't nasty or anything, it sure was embarrassing. Luckily I am now the person in charge of updating bios. I immediately changed it to an almost-generic sentence.
I'm afraid I can't answer much about the rates or anything else because I mostly write for print.