Builds on my recent observations that it is the questions you ask as much as the answers you get that are important. And you can't ask the right questions unless you have complete data as you don't understand the big picture.

In my early days as a product manager I relied on samples to research consumer behaviour and motivation. Big Data offers the change to analyse the big picture and not rely on sampling.

Advise you to link through to John Balls's blog for the tale of the " Blind Men and an Elephant" to realise the important of seeing the big picture including data outliers.

Outliers may indicate a serious flaw in your picture of the world and/pr the algorithms driving your business