Why have a personal domain? A domain, along with appropriate hosting, makes it possible to run a server: a computer system on the internet that responds to user requests. Some servers provide music streaming or software repository services. Others carry out some sort of computation — bitcoin mining or fluids simulations. One common server setup pairs a web server like Apache with a database back-end like MySQL.
tedm.us has grown and changed over the years. I now use the SSH server and an rsync Python script on my laptop and workstations to synchronize my data. The website, originally hand-coded in HTML/CSS/js/PHP, is now written mostly in Python/Django/Bootstrap. (This shifts much of the code maintenance to the web framework developers.) There are a few web apps in the private section of the site that help me stay organized. And hardware duties are now happily outsourced to a Linode virtual private server.
Have a look around. Running a server is a great way to build technical skills. In the wiki, I give my two cents on various pieces of software, etc. that can be useful in science research and system administration.