Sparked by this meta, I did a quick search for "socket.io" and came back with 21 hits. It seems to be enough to create a tag for it IMO, but I'm no web guy. I don't really understand what this framework is and if it really applies to these questions.
A lot of these questions are currently tagged with websocket or socket and I have a feeling that these tags were just "close enough" when the OPs posted and don't really apply, but I'm not really sure. Can a subject matter expert chime in and let us know if it a socket.io tag would be appropriate on these questions? If so, perhaps someone would be willing to take a look at retagging? It's only 21 questions. It shouldn't take more than a lazy Sunday for one person to clean this up.