My husband sort of bullied me into announcing on FB.
He can't keep a secret TO SAVE HIS LIFE and one night he said "Okay, I don't care what you do, but I NEED to post it on Facebook!" Obviously, we have a lot of mutual friends, so I figured I'd get busted eventually. My announcement was pretty vague and obviously not everybody got it. (I referenced the Michelle Shocked song 'When I Grow Up' and wrote "we're gonna have 120 babies....or maybe just 3". My close friend that know how much I LOOOOOOOVE Michelle Shocked totally got it. On the other hand, 3 weeks later I'm still coming across people who completely missed it. Admittedly, I have a really large friends list with a lot of work associates, who also have very large friends lists.
I DID make sure to tell all of my close friends a family before I posted it.