There are many different methods you can use for promoting your old blog posts. This tutorial suggests you two different methods for promoting your old blog posts automatically.
Old Post Promoter (OPP)
Old Post Promoter is a free WordPress plugin that automatically promotes your old blog posts. It randomly selects an old post and resets the publication date to now and hence promote older posts from back to the front page and also in RSS feed. So your post automatically visits to your subscribers and get published to connected social accounts.
After activation visits its options page from admin area, it lets you set minimum interval between old posts promotion, randomness interval, post age and more. You can even set the post position where old blog post appears after promotion.
Tweetily – Tweet Your Posts Automatically!
Second best plugin you can use for promoting you old blog posts is “Tweetily – Tweet Your Posts Automatically!“. It allows you to promote old posts by tweeting them to twitter automatically with hashtags. It is provides you many useful options, set it and forget about it.
Install and activate it, then visit Dashboard -> Tweetly. Connect your account and select your options. It lets you set tweet interval time, number of tweets to do, maximum and minimum age of post, categories to exclude, additional text before or after the actual text (you may use this for adding ‘RT’ and ‘via’ etc), even you can set it to automatically create hashtags from post tags or categories.