There generally isn't too much commenting going on though, despite generating a decent number of views. This makes sense - I only give feedback to a small percentage of things I see on the internet. I would like to interact with other designers more, but sending unsolicited comments/criticism via a tweet or an email doesn't seem appropriate most of the time.
I included a small note on the bottom of my last project "Have an idea for another graphic? Think I did something wrong? Hit me up! adam.r.pearce@gmail.com | @adamrpearce" which resulted in a couple of interesting email threads. None of those conversations really need to be private though.