Your online profile is less a reflection of you than a caricature.
Whether you like it or not, commercial and public actors tend to trust the string of 1s and 0s that represent you more than the story you tell them. When filing a credit application at a bank or being recruited for a job, your social network, credit-card history, and postal address can be viewed as immutable facts more credible than your opinion.
But your online profile is not always built on facts. It is shaped by technology companies and advertisers who make key decisions based on their interpretation of seemingly benign data points: what movies you choose to watch, the time of day you tweet, or how long you take to click on a cat video.