The main purpose of the site is for communication of information related to the author's activities. Content includes distribution or course content (free or professional), development and testing of web pages and applications, etc. This activity is much more efficient on the owners personal server. Also, use of a personal server in many cases provides an opportunity to utilize or develop tools not available through professional affiliations (such as university servers).
As a personal web site operated on an individual's server, some content is intended only for friends, family, students, or authorized users and is not open for public use. Any attempt to access unauthorized or private content is expressly prohibited (note criminals and hooligans don't laugh too much, and the server used is not very interesting and can be wiped and restored easily if compromised).