The simple answer is: because we can and because it is cheap. Since the 90s and the dynamic web pages, we as developers have the power to create online forms, capture and save the data via server-side programs.
Then we realized that we didn’t need a form. The web browsers were providing plenty of user information we could collect.
A simple PHP pixel triggered via a <img> tag was all we needed to capture users’ information and save it in a MySQL table.
Until now, we didn’t question if we were allowed to save so much data about users, why doing it, and which data is it going to be used for business purposes.
With the emerge of big data, machine learning, and privacy concerns, we are entering a new era where the quality of the data does matter.
Do we have permission to save this data? Is it going to be helpful to improve the user experience? Does this data help us to predict business outcomes?
With so much CPU power, infinite storage capacity, there is no point in saving all the data just in case we need it in the future. Now we can stop, think, ask for permission, and think backward: if I want to improve my customers’ lives, what data do I need from them? If I want to build a sustainable business, what information do I need from my customers?
(Interested in learning about the story of data? Check this blog post.)