There are many reasons why your should choose WordPress for your next web project. One of the first reason is that its free. Its both free as in free beers, and its open source. You can go to wordpress.org and download the source code and install it on your own web server, or you can go to wordpress.com and sign up for a free account on a shared web server. The .com-version does not have all the features as if you have your own installation. But if you install it yourself on your own web server, you can install what ever theme or plugin you like. That is not something you should do, without knowing that there aren’t any security holes in the plugin’s (or theme’s) code first.