“Web analytics is a set of strategic methodologies implemented to maximize online and e-commerce activities. Web analytics extracts and categorizes qualitative and quantitative data to identify and analyse on-site and off-site patterns and trends. Analytic techniques and requirements vary according to organizational requirements”. 
Web analytics is a very good tool for websites, it allows them to know what people are looking for on your page, how long they are staying on your page and also where you’re paying customers are coming on the internet.
A few years ago Google researchers announced that they could track the spread of influenza across the U.S without needing a single medical report. What is interesting they were able to do it quicker than the Centres for Disease Control and Prevention (CDC). Google were able to do this by simply finding a correlation between what people searched and whether they had flu symptoms. The engineers didn’t develop a hypothesis about what search terms might be correlated with the spread of the disease itself. The team just simply took their top 50 million search terms and let the algorithms do the work.
I find this example very interesting. The simplicity of tracking the outbreak of any disease is very important in preventing the spread of any of these diseases. There is so much good that could be done with this data. This data seemed to be very
accurate but four years later after using this data for several winters, the theory free data rich model had lost its accuracy and was having trouble tracking where the flu was going. It turned out when the C.D.C produced its steady data it showed that google had overstated flu like illnesses by a factor of two. The engineers could not know or being to know what linked the search terms with the spread of flu, the engineer’s weren’t trying to figure out what caused what, they simply found statistical patterns in the data. In others words they only cared about correlation rather than causation. These methods were much cheaper and easier set up.
As I said earlier this data could be used for great things but there is also down sides to it. Bad information or inaccurate information could be very dangerous and could make things worse. The flu is not one of the worst diseases in the world but just say it was something more serious, this inaccurate information could cause panic around countries affected by serious diseases. 
Web analytics is only going to get bigger with retailers trying to find more and more ways to get sales and information about people. I personally find it a bit too much I find it very unnerving that complete strangers can have so much information of you.
I know there is rules and regulations about the mishandling of personal data but having all this information about people floating about cannot be good. Yes there is benefits to all of this gathering of data but in the wrongs hands people can find out fairly important things.