When I started thinking about having a homepage I had the following uses in mind.
A repository of information; useful to me (primarily) and to others (maybe :) ). This includes bookmarks, some articles, resources... A personal homepage has one major user... its author!!.
A journal for my plans and projects Whenever I have something in mind, I know where to keep it :). Be it the exploration of a computer program, a future trip, an event...
A communication facility: I would like to use this page as a means to have friends and colleagues aware of my activities, interests, hobbies, adventures... and not having to send general emails anymore!!.
A exploring tool The web offers a lot of features and my service provider offers some interesting capabilities to explore (PHP, MySQL...). In the long run I foresee owning and administering my own server machine (typically a GNU/Linux box in the basement :).
So, as you can see, the reason for being of this website goes far beyond a professional or commercial purpose. It will be a very useful thing for any activity to come.
If you are also interested in doing a similar thing, I invite you to see which services and tools I am using to build this site.