Once you’ve built an audience and a large library of old posts, it is possible to drive readers back to them if they contain non-episodic, reference content that continues to have some relevancy. Twitter and Facebook are great for this because you can use them to notify readers of existing posts and increase audience interaction, without requiring costly new content development. Contrast this with RSS, which only notifies readers about new posts and can’t promote posts out of order or in a cyclic and seasonal manner.
Chance are, your blog’s older posts are buried deep down in your archives and if they didn’t get a lot of comments when posted, they probably are not highly ranked in search results today. By driving your audience back to these old posts, you can increase their keyword and content density because you have an audience that is now large enough, and primed, to leave comments on your posts.
More comments = higher keyword density, so recycle these posts and generate more organic search traffic. It’s a beautiful thing.