Web analytics is the measurement of the behaviour of visitors to a website or web application. In a commercial context, it especially refers to the measurement of which aspects of the website work towards the business objectives; for example, which landing pages encourage people to make a purchase.  It is meant to give insight on where your customers come to your website from, what search engine keywords are used to find your site,  how many visitors, per day, from where in the world.  Know if the users visit your website on a windows or mac.  There is a huge potential to use a tool like this to enhance your business with your existing clients as you can drill down into how they use your website completely transparently.