How do you decide who to put in your fluther?

I was boredly wandering around the options here, since it seems like no one is on, and I looked at the people who had fluthered me, and there were a number of people I didn’t know. Not only did I not know them, but I had never seen them around.

It was odd to me, because I put people in my fluther when I have seen what they have written, and it speaks to me. Usually, but not always, I have interacted directly with people, either in pm or in discussion, and it is this interaction that prompts me to put them in my fluther.

How do you decide to put someone in your fluther?