Sentence:  “The company sent a flood of tweets—actually, we ought to call it what it was, an epically disastrous <WSD>tweetstorm</WSD>—aimed squarely at journalist Nancy Jo Sales insisting that the app is about "so much more" than hooking up.” 
Meaning of the word marked with <WSD> tags:  A series of tweets posted on the Twitter microblogging service in rapid succession.