Having a goal for your website is vital but you need to measure results to see how you're performing. The goal for a website will vary from one organisation to another but many metrics can be tracked using Google Analytics. This free tool provides much more information than you get from the statistics package provided by your web host.
Getting Google Analytics working with your Joomla site used to be a bit tricky but now it is super easy when you install a free extension by BIGSHOT. Just install it, edit it in Plugin Manager and add your Google Analytics tracking code.