I loved this passage in a talk given by Stijn Debrouwere who works at The Guardian:

The metrics you’ll need will depend on your business, but as a starting point I like Dave McClure’s list of five startup metrics for pirates:

1. acquisition: finding new users
2. activation: getting users to give your product a try
3. retention: making sure those users stick around
4. referral: have your loyal users invite others
5. revenue: hopefully you get to make some money from all this

Acquisition, activation, retention, referral, revenue, or, as an acronym: aarrr! Those are usually the big five things you have to worry about.

As he says, the most important thing to remember is to be really specific about what you are trying to achieve. We are all drowning in data, so it’s refreshing to get back to basics once in a while.