Personally I make it a point to interact with anyone that responds on one of my posts. If I don't feel like what they said requires a written response I still upvote it so that they know I am at least acknowledging that I read what they said. I feel that if people are going to take the time to interact and show interest then I need to acknowledge that. It's not long ago that I recall exactly what it's like having no one interested in what I was saying.