My reasons being:
The PFB threads on here strike me as stealth boasting about what a good mother the poster is ie. "oh I read the works of Shakespeare to my one week old, wove her clothes by hand and only fed her organic veg that I grew in my own garden - ha ha aren't I silly!"
It makes me feel guilty - I had a lot going on during DD's first year so I didn't really have time to worry about the finer details, and I would have left her with the local postie had he offered, just to get a break. I would say I have a very relaxed parenting style but when I read those threads I feel like I SHOULD worry more about the little things (not confessing my lax mother mistakes on here, unless someone else goes first!!)