Unrequited Sub 

When you subscribe to someone on YouTube, hoping for "Sub for Sub," but they don't subscribe back.

Tr0llinN0NST0P was hoping to get a "Sub 4 Sub," and subscribed to NYANRainbowz. He checked his channel later, realizing he had experienced an unrequited sub.

Unrequited Sub by TehPurpleIce August 22, 2011