Depends on the time, if it’s the middle of the afternoon, it's a welcome break from the tedium of work so the reaction would be:
Ooh! I got pinged, what’s this?
If it’s 2am and the ping woke me it is more:
Whom Pingith me? If this is not of Earth shattering importance, I shall burn your village and pillage your women!!!
(Or post grumpy cat gifs, whichever is easier)