Update: Seems like YARPP plugin has been pulled out of official WordPress plugin repo. I will keep you posted when new plugin is added. For now, you can check out YARPP alternatives.
Related posts on any blog is very useful from readers and bounce rate point of view. A related post plugin, shows the most closely related post to the topic, your reader is reading. Different WordPress plugins uses different approach for showing relatedness and one of the best WordPress plugin which I have found to show related post is YARPP a.k.a Yet another related post plugin. This plugin uses many factors to show related posts and this is a plus and play WordPress plugin.
YARPP can be also configured to show related posts in feed which is very useful to get extra clicks from your feed readers. Specially for huge blog, this is one of the best related post plugin for WordPress as it uses the caching mechanism. This means, plugins will not keep generating related posts on the fly, instead once related post is generated for a post, it will show it from cache, which stops this plugin from increasing php calls.
Once you are done installing YARPP plugin, you can access it’s setting panel under Settings > Related posts(YARPP)
You can automatically enable to show related posts or you can use custom code to show related posts at specific place. YARPP can also be configured to show related posts with thumbnail by using custom template.
You can scroll down further on the setting page, you can configure various options for showing related posts in feed. I will highly suggest to keep description off as it makes related post looks like little busy.
In case, if you maintain one such category or tags which you don’t want your readers to see again in related posts, you can exclude such categories or tags. I would suggest you to create a specific tags for outdated content and exclude it using this plugin. This way, your readers will see only updated and useful content. You can also exclude pages to show as your related posts. One more reason that this is one of the best related post plugin because in last 1 and half year, this plugin has gone under lots of iteration and this is constantly updates and compatible with latest WordPress version.
Showing related posts below blog post is one of the most easiest way to decrease bounce rate of your blog and if you are running a WordPress blog, YARPP is one of the easiest way to add related posts to your WordPress blog.