I found in one of the FAQ's that Sphere is a good thing for finding related articles. So I went to sphere, and they have a widget that can be uploaded to WordPress. But I don't know how to follow the instructions for uploading the widget. It says 1. Copy the file sphere-related-content.php into your plugins directory (wp-content/plugins/). I don't know if I have such a directory. Is this related to the http://www.wordpress.com, or is it for people who have their own wordpress code? If it can work here, please tell me how.
P.S. Is my "Profile" URL supposed to be my wordpress url, memorywriters.wordpress.com?