Some really great points so far I'm not sure I have much to add!
I too have been a bit bothered by the lack of warts-and-all discussion on parenting, pregnancy/birth etc that I've experienced with my friends. Maybe on BB we are more comfortable with the 'TMI' because it's more anonymous, or maybe I just have a circle of friends who are more 'stiff-upper-lip' than I would like them to be at times. I find that when we do get around to the frank discussion on the bad bits of being a mum, it seems to turn into that old competition about who's got it worse, which I don't like. I don't care that so-and-so feels they have a harder job than I, I just want to know that someone else is going through it and can commiserate, not compete, kwim?

It could just be because I'm a chronic motormouth - I have zero qualms about laying bare all the joys, challenges AND the frustrations of being a mum. I don't at all buy into this 'supermum' bs, it's a lie. We have good days, we have bad days - and depending which day you catch me on, motherhood is either the most supremely awesome invention ever, or it's a living nightmare from which I have no hope of escape! I'm not ashamed to say it out loud and be proud that I can admit to the struggles as well as the wins.

For me, talking about all this stuff depends on who I'm talking to - for instance, if it's a friend who is expecting or TTC, I try to steer away from the negative aspects or at least gloss them over so it doesn't come across like I'm trying to scare them; if it's a friend who has kids older than mine, it's more, 'Oh my goodness wth is wrong with these kids?! Did yours do this?! HELP MEEEE!!!' And with any scenario, the worst thing is when they get that 'shut-down' glaze in their eyes, like I'm betraying generations of women before us by admitting to faults or that kids aren't always angels. It's like, come ON, be real here - mine can be little terrors and I KNOW yours are too!