Three steps to starting college: Meet roommate. Unpack in dorm room. Then, sometime during orientation, hear music, see a student start dancing, watch as more dancers join in, and join the campus flash mob. (Or if you miss the actual event, watch it over and over on YouTube, to see how many people you recognize.)
Outbursts of seemingly impromptu dance numbers were so common at orientations this year that BostInnovation, a Web start-up chronicling Boston life, ran a contest asking readers to watch the YouTube videos and vote for the local campus — Wellesley, Merrimack or Emerson — with the best welcome. (Wellesley won.) There was even a flash mob to greet new students at a medical school, the University of Alabama at Birmingham.
The college-sponsored performances, which have grown to feature coordinated costumes and appearances by tweedy officials, sometimes suggest the dance equivalent of the school fight song, a far cry from the roots of the genre — informal gatherings hastily called via social media.
Nonetheless, their popularity is growing.