So, I’m guessing as a direct copy of Google+ circles, Facebook has created lists. Foreveryone not on Google+, so most everyone, you can arrange everyone you know in circles. You can then sort your feed so that you are only seeing one circle at a time if you want. Facebook lists are doing the same thing, so will that slow the progress of people potentially switching? I dont know.
Facebook’s huge problems lately have been about censoring news feeds to only give people information and statuses from those they interact with the most. This effectively filters out a lot of constructive diversity unless you take special care to visit different friends pages and talk with everyone. Lists seem to be more of the same, only worse. In my opinion Google+ can get away with it because up until this point they have not been censoring or limiting anything in a feed. (Note: it hasn’t seemed necessary yet with the very little activity that I have seen there) Facebook is already filtering the “news” we see, then will let us filter further with lists.
On the other hand, if you bother to create lists of people who you would like to hear from but are afraid they get filtered, you can, and check it every once in a while to see what they have been up to. I for one, have not created any lists of my own and an not planning on it. But I could see lists being very useful for members who are very active in causes or politics.
Facebook is still winning in members and use, but in my opinion Google+ has more credibility with the whole circle idea. Less advertising and trash and fake profiles (so far). It might be hard to evaluate if the new lists will affect Google+ since we don’t know how its growth would have turned out otherwise. But I don’t believe it will change the number of people who are willing to switch away from Facebook.