ONCE UPON A TIME there was a philosopher by the name of George Berkeley (1685-1753).  He concocted a theory of knowledge called immaterialism, later to be known also as subjective idealism. An immaterialist denies the existence of material substance and instead holds that objects are only ideas in the minds of perceivers.  As such, things do not exist without being perceived.
In Latin we would say esse est percipi:  to be is to be perceived.
Now three centuries removed from Berkeley, I propose a new theory of knowledge for our Age: Internetism.  In Latin that would be nisi internetum non entia which translates as UNLESS IT'S ON THE INTERNET IT DOES NOT EXIST.
Today events take place in Cyberspace.  It is a virtual environment, which is to say, a place removed from the material world.  We obtain information from the Infosphere.  We form virtual communities in the Blogosphere.  In these sub-units of Cyberspace there is no substance, yet there exists a unique, eerie physicality.
"In this silent world," wrote John Perry Barlow, "all conversation is typed.  To enter it, one forsakes both body and place and becomes a thing of words alone."
We live simultaneously in parallel worlds.  One is physical; the other, virtual.  The more time we spend in Cyberspace, the more real it becomes to us and the more it tends to replace the material world.
One no longer shops; one orders on-line.
One no longer visits; one interacts with unseen fellow travelers in Cyberspace.
One no longer speaks; one uses a keyboard.
The oxymoron of our Age is ... social media.  There was a time when, to be social, people actually got together.  They talked; they could see each other; they could even touch.  But today, in various so-called social media, interaction occurs in a virtual community, sight unseen.  Anonymity often masks reality.  It is immaterial.  George Berkeley would love it.