A few other observations about Facebook that could help Google+ succeed:
1) I can't really explain why (other than poor boundary setting?), but I have people in my Facebook friends list who I can barely tolerate. I added some of them because of apps we both used, met a few of them online, and met the rest of them in real life, but it stresses me out to see their posts. While I understand that I could just remove them from my wall feed and be done with it, there are some cases where I don't feel like completely removing them from my feed or my friends list (for example, if we both play the same game, but their personality irritates me). I think that this is an aspect of social communication, having members of your social life who you don't really like for one reason or another (in laws, maybe?) and still needing to interact with them at some level. It would be nice if Google+ allowed for a less black and white approach to keeping these people further out in our "circles". Maybe we could set up where people actually appear in a visual diagram of our social friendship network, and then adjust interaction settings for those different levels of interest, or something?
2) While I understand the idea behind only allowing a "+1" or a "like" to dissuade people from seeking attention through negative behavior, there are times when I do want to continue a discussion I'm having with someone on Facebook in a comments thread without continually trying to figure out if they replied to me or not by manually reading through the comments. It would be nice if in whatever the "comments" feature here will end up being, we could click "reply" on someone's post, be sent down to the comment field, and then have them receive a notification when I post my comment in reply to them which would take them directly to my comment. It would be extra nice if, when using that feature, The person's name could be included as a link in the top of that post with some kind of @username kind of thing that when clicked would scroll the user directly up to the comment I was replying to. This would allow a sort of "meta commenting" to occur without blending conversations in a comment thread into chaos.
3) On Facebook when I comment in a comment thread and then someone "likes" my comment, I receive a notification that someone "liked" my comment. When I click that notification, it takes me to the top of that thread and then if I want to see if anyone who liked my comment replied to it or what kind of people are liking my comment, I have to either pick through the entire list (usually hundreds) of comments to find my comment, or expand all of the comments click by click and then use my browser's search feature to find my comment again, by which point more people have liked my comment and posted, and I sometimes have to start all over again. This way of doing things feels particularly ridiculous when I know that the notification that people liked my comment could (and probably should) take me directly to my comment. Better still would be to be able to immediately see a list of replies to my comment and read them as a discussion.
4) Sometimes no one "likes" my comment, but I'm still curious about who replied to my comment. To find out if anyone liked my comment, I have to manually find that comment thread again, hit expand a bunch of times, use "find" to find my comment by my name, and then read down through potentially hundreds of comments to see if anyone was trying to reply to me. I could search by name, but they may have misspelled my name or even chosen to reply to me without using my name (or deliberately parodied, or used a nickname they have for me). In one particularly egregious case, a comedian I follow had posted a personal family problem he was having, and 5,000 people commented on it. I posted a personal experience of mine and some supportive messages. When I went back to see if anyone had identified with my personal experiences, or felt that they were helpful I had to spend a half hour hitting "previous comments" trying to find my comment in a list of 5,000 comments only to get all the way to the beginning and accidentally click the post link, contracting all of the comments again. That is just not good usability.