Thank You OP for a very detailed description, however a diagram would have been easier to grasp IMHO. I have an online training courses website with courses on different topics, plus whitepapers (free) and some free courses. Also the usual About Us, etc. Would this be a correct silo structure? Are the interlinks between the topic pages allowed (because one course can be common to two broad topics). Also in this kind of structure how can I display a main catalog page that shows all the courses together?