"Web analytics origins from the lead based businesses"
This line covers the answer for the second part of question. I will attempt to explain it for the first part of the question.
There are various types of web analytics
1. Google analytics - this gives view of people who have landed on your website. Trends of such appearance are based on time, place and gender.This is usually linked with any kind of changes made in our website or its promotion strategy which gives us the best strategy for making a websites visibility better based on which change attracted traffic.
2. Heat Maps- this is a lesser used web analytics, it gives us an insight into what parts of a website page or which page customer spends time on. A cause and effect relation is established to lure more customers into subscribing or buying products. For eg customers mostly return on "cart" page after spending a lot of time and re attempts to pay..
This means that our payment system is not customer friendly
3. A/B testing- this is a startegy that is not only applicable to web but in real world also. In this two feasibile versions of same product are launched and consumer behaviour is judged to know the better one. Sometimes both are equally good in different segments of people(eg male and female)
4. Marketing tools like SEO, PPC, SEM, Social media marketing- all these are based on this startegy itself, but these are used by marketing companies instead of website owners
In todays world every business runs on consumer behaviour except for necessities.
Even the smallest business can implimemt these at any level to give a nudge to their business.