Ha ha, FrothyOM
I read the OP article with a 
face. I don't have a Facebook account, but I really don't think there is a valid argument against a woman being able to put a pretty picture of her choice on a fairly trivial social networking site. I have photographs of my baby and my cat on on my Mumsnet profile but none of myself; what's wrong with that? I think the author of the article is suffering from too much overthinking and too little ability to form a valid argument.
I am utterly subsumed in being the mother of my 16 week old daughter: Wordsworth's lines, "Light to the sun and music to the wind," spring to mind. Inasmuch as I subscribe to the theory that we are defined by our genes (not very much, to be honest), I believe we must be the end product of thousands of good mothers who have blessed us with their instincts and ability to devote themseves to raising healthy, successful children. I am grateful for that inheritance. Babies are completely dependant on us; of course mothers focus on their children's wellbeing for the few, precious years that they need. I have a degree; I speak 4 languages; I have a library of more than 10,000 books (including at least 300 volumes of feminist dissertation). Why should this be more important in defining me as a woman than motherhood?
Giving birth is the hardest and most wonderful thing I have ever done. I now have strength and capability that I never dreamed possible. It has even inspired me to start writing again after 13 years; the first thing I wrote, 4 days after my baby was born, was a very frank, completely tmi and rather good (even if I say so myself 
) account of my labour in the Childbirth section on here. If I hadn't become a mother, my talent for writing would never have been used again.
Like Xenia, I went back to work after 2 weeks (okay, slight boast, partly because I could get back into my pre-pregnancy clothes) and I've managed to combine this with successful breastfeeding. I enjoy my job very much; it is challenging, fast-paced and stimulating. Yet my job could never compare with the bone-deep satisfaction and pleasure I feel when I am caring for and nurturing my baby. How sad that the art/skill of being a mother is so belittled, especially by women who are mothers themselves.
*I wrote a much longer and, hopefully, more elegant post but lost it 
. This is the gist anyay.