Well, it's up to you why you follow anyone, but following people for their comments at the very least puts their comments into your 'chatter' feed. Personally, I like chatter a lot, but most people seem to not really care about it. I thought it would really encourage more talking, but I'm not sure how much, if any, impact it's had.Correct me if I'm wrong, but you really shouldn't be following people for "good comments," as the follow feature has nothing to do with whose comments you see.
Oh, I didn't even know that. I don't use chatter. I guess I prefer to talk about a specific subject over the span of a day than talk about something I don't necessarily care about with much prompter replies. Maybe I don't know what the point of chatter is.
The point of chatter is just to see what others are talking about. Maybe there's a story that you wouldn't click on, because it doesn't look interesting to you. However, conversations meander in all sorts of ways, so maybe there's an interesting conversation on an otherwise uninteresting story. Or, maybe there's a conversation going on in a story that's not in your feed. You might find it there. Chatter helps users to find such conversations without having to browse everything. Obviously it doesn't work as efficiently as I had hoped.
I think part of the problem is that I already see nearly every damn thing that anyone comments on. I was talking to mk about this yesterday: I follow so many people, tags and domains that it's really rare for something to pop up on my feed because it was shared there, not because I was following the poster, tag or domain (only 1/20 on my feed now; same when I was thinking about this 24 hours ago). So I tend to catch most of the conversations without needing chatter. I also have a limited time to hubski that I mostly spend with notifications, submitting or the first 15 posts on my feed. So I'm not chatter's target audience, don't despair.
I like chatter because it reminds me of conversations I thought died down. Sometimes it takes a day or two before somebody replies to an interesting conversation, and by that time it's not on my feed anymore. I don't feel like checking for new replies constantly, or simply forget because in my mind I've already read all the replies (like in this conversation for example). Chatter allows me to circle back and revisit older posts, which is pretty nice.