Vanity metrics are just numbers which can be manipulated and doesn't add business value. Cohort analysis is more deep into analyzing behaviour and breaking down micro data sets to take decission and converting it into action.
A website has many points to collect data from a user like downloadable contents, subscribe to blog and etc. An analytics applicatin can collect a lot of data from a user while visiting a website, but the real problem is how to classify it under one head and what action has to be taken after making a decission.
Real time analytics is playing a huge role in learning what a visitor needs. How about guiding a user in real time when he is browsing website? TeamRocket has the capabilities to track, guide and nurture a visitor in real time without any impedence.
With a humongous amount of data present in different segments what can you do with it? Decision making with raw data doesn't make any sense. Processing raw data, chunking out junk data and arrive at meaning full information will help a business to forecast the future.