My problem with lists is it acts as a separate group rather than a filter. I want to see everyone's posts who is in a list. Instead I only see posts that have been specifically shared with a list.
With circles, it automatically filters my stream without anyone having to post to my list or group. They just share it with me.
People don't post to a list on Facebook. Your friends don't even know they're in a list, like Circles. You can filter your stream by lists, but it's not exposed on the UI and you have to do some URL mingling.
With circles, it automatically filters my stream without anyone having to post to my list or group. They just share it with me.
This is a subtle but important difference for me.