The new related posts feature works on all themes hosted by WordPress.com. Everyone with related posts has the ability turn it off via Settings-> Reading in the Dashboard.
The Expound theme has its own built-in related posts feature.
The quotes below are excerpts from replies to comments by Staff in the announcement and replies in support forum threads to questions about related-posts.
1. A minimum of 10 published posts before we show the Related Posts section, otherwise we will end up just cross linking every post with one another.
2. At least 500 bytes of content, which is about 100 English words, in a post before we try and find related content.
3. Relatedness of the post currently takes into account the post title, content, tags and categories. We are constantly tweaking our algorithms and hope to improve on the quality of the results as time passes.
4. We will use the featured image as the thumbnail if it exists otherwise we will fallback to the first image in the post body.
- If there is an image from a 3rd party in your post as long as it’s publicly accessible we will use the WordPress.com servers to pull the image in, scale it to the appropriate size, then serve it as the post thumbnail.
- Unfortunately there’s no way to adjust thumbnail sizes at the moment, we’ll look into supporting custom sizes in the future.