It does irk me when a profile pic is anything other than the person in question. It's all very well saying 'I want to share that photo with people', but you can upload photos to Facebook without making them your profile picture! Your profile picture goes next to your name, to represent YOU. Ergo, it should be a photo of you, surely? It's more the misuse of purpose than anything else to me, but then I am extremely anally retentive about these things 
I do see the point of the article, beause of the above too; it's supposed to represent you, and you are now/should not be solely defined by your children.
On the informed consent issue, an aquaintance of mine posts photos of her 1-year-old DS on Facebook, naked, all the time. If anyone says anything to her about it she basically tells them they've got issues and are sexualising her child and explodes at them. MY problem with it, however, is only that it's his body and he has a right to privacy which she is not respecting. I hate the photos of me naked as a child, and my mum doesn't even show them to anybody, she just has them. If I knew they'd been on Facebook... Well, it doesn't bear thinking about.
Just my thoughts 