Is Unfriend Even A Word?

I unfriend in a somewhat random way.
Not in response to something said to me,
But in response to broad polemic spray,
A splatter pattern there for all to see.
Plus, as a rule it's someone I don't know,
Don't know in flesh and blood reality.
They do not notice that I choose to go.
I just evaporate from their big set
Of faces in the social network flow.
Not one has called to say they miss me yet.