Mendeley Related Research finds academic research related to your blog posts from http://mendeley.com.
It is based on the blog post tags. Therefore it is important that you add tags in the 'Post Tags' section when you create a new blog post.
It is recommended to use at least two tags, but not more than seven. Additionally, the tags should be descriptive.
Go to http://dev.mendeley.com/
This is most likely due to the caching. It is set to 12 hours by default. You can either wait for it to expire or clear the cache by going to 'Settings' -> 'Mendeley Papers' in the WordPress admin panel.