I sometimes read and answer comments. Same goes with notes. I don't mind if you thank me for the watch, llama etc on my page. If I can, I will say thank you and give a llama back. I don't bite, so simple comments like "hi" or whatever are cool.
OPINION BASED WORKS
Just like anyone else here, I freely give my opinion on certain subjects. However, having in mind the dA rules. Sometimes I will or won't allow comments, it depends on how I feel about it. I will not respond or engage in flame/hateful content.