Leave commenting on for ongoing discussion.

This can keep an old post relevant. Just because you wrote an article a year ago, does not mean that people will still not add to it, and sometimes people will link to articles based on comments that are left. Share old posts through social networks if they are still about relevant topics. You dont want to just start flooding your Twitter account with tweets to all of your old content, but if you have an older article that is relevant to a current discussion, you may share it, as your take on the subject.