According to Wikipedia, Analytics is the discovery and communication of meaningful patterns in data. That’s nice and all, but what does it mean in day-to-day terms?
What patterns are meaningful and what should you be paying attention to? How is this useful and not just mental masturbation and a time suck?
The data that’s relevant in terms of your site are mostly concerned with user activity. That’s a no-brainer.
Deciding which activity matters requires a bit more thought. For different sites, different data is more or less important. The image at left gives an inkling of what’s commonly considered useful.
One thing you can almost ignore is raw “hits” – that is, the number of requests for files on your server. This is the metric most commonly paid attention to and talked up by amateurs.
Sure, it’s relevant, and as a broad metric it does give you an idea of how busy your site is and when, but that data is really only useful if you can also get some idea of why. That’s where more detailed analytics can be of service.