With your installation of Joomla!® you can create anything from a simple website to a very complex website with hundreds or thousands of visitors.
Joomla can be extended to virtually any level you want from your website: from telling people of your travels, experiences, tips and hints, to selling products and services.
You can sell physical or downloadable goods to subscription based services.
Joomla can be used by anyone - regardless of age, background or skill level.
The skill level that you reach is determined only by your own desire to do more and learn more.
If you choose to install the default Joomla content it is probably advisable to "unpublish" the default content articles.
Otherwise doing a "Google Search" will reveal default content pages of a Joomla install that contain an article titled the same as your Google (or other search engine) search query, when your website itself is nothing to do with Joomla.