Sort:  

The small encouragement may mean little to you, but to the writer it's an incentive to continue creating original content. A burst of confidence, if you will.

Okay, it may make you feel good, but is it actually honest? or is it just a nice comment to get upvoted? is it critical and does it help you to improve? I'm not saying nice comments are bad, I'm just saying mean, honest comments (when constructed well) prove to be more helpful.