Short messages on services such as Twitter may be tagged by including one or more hashtags; words or phrases prefixed with a hash symbol (#) with multiple words concatenated that help ‘define’ an event, trend or purpose.
Here is a list of some of the most useful ones in our industry (in no particular order)…
CES, Las Vegas
NRF Big Show, New York City
Integrated Systems Europe, Amsterdam
Digital Signage Expo, Las Vegas
Common Industry Terms
Our sister site aka.tv  monitors event hashtags during the appropriate show times.