This is good advice. In all aspects of life. Including online. Do you chase after people online that never give you the time of day in return? Never read your tweets, posts, updates when you constantly high-five them?
Stop feeding the egos of narcissistic people who feed off the joy of ignoring the people who admire them. If the person is someone in your field that you like to follow, then admire them from afar, but stop giving them more fodder to make themselves feel more superior and you feel worse.
A narcissist is a narcissist is a narcissist. They ain't ever gonna change. So move on and give your attention to people who deserve it and care about you back.
There. I feel better already. Don't you?