I find that I am using LinkedIn less and less these days. It is an easy way to keep a contact list (the adding part, but I never use it to communicate with). Facebook does this better, so I think Facebook could completely replace them if they add ways to group your friends and allow you to control what you share at a group level.
It is a start, but it doesn't allow you to share say a link to HN for only your hacker/business peeps and a "the baby just did this" for your friends/family. As is, the HN link would just confuse my family (and maybe scare them) and nobody but my family wants to know that my boy just drove his car down the stairs.
Yes it does. Click the lock. Select "Specific People" and select the appropriate list.