One thing I have done for my blogs is automatically turn off comments after a short period of time. This may cut down interaction a lot, but I feel that it is necessary. Let me explain why.
Years ago I had a podcast called DogearNation. We based this podcast on the very popular DiggNation podcast… Meaning we found cool links people posted on social media, and talked about them. The cool thing about this model was that we had tons of content, which caused a ton of interaction with our site. This content had a long shelf life, and people would find both the podcast and website for a very long time. The problem was, since the content was long lived, comments were used by spammers to post links for phishing and other problems.
I have since changed all my blogs so that comments are enabled only for a few weeks. So my question is, does this give you enough time to comment on a post? Should I extend it? Does it matter?