It's a feature that can be worked into Facebook in ways that will be far superior to starting a whole new social network. Google is fighting a losing battle here because they seem convinced that people want a clone of Facebook with a few extra features. And it's just not true.
I use granular settings for messages I post to Facebook. I also use the new "private groups" on Facebook a lot.
(I just tried to show a link to the "private groups" feature on Facebook, and that proved to be very frustrating. It took me a while of thrashing around with Facebook's help feature--after first trying Google, ahem--to find the main page about Facebook groups
to show those of you who haven't tried them before. The private groups posting interface differs in some weird ways from the usual posting interface on wall posts and private messages, as typing "Enter" instantly posts the message, and the only way to form paragraphs in text is to type Shift-Enter, which is especially confusing for Mac users.)
It will be interesting to make the comparison between a new Google offering and Facebook. Any product or service that offers social interaction has to help each user build a network among the user's friends. Buzz was a big fail that way, as most of my friends immediately decided not to use it, but perhaps something new from Google will be more successful. My friends are all smart enough to know how to bail out of the second-best network if something better than Facebook comes along.
