Flashmobs were something of an 'underground' movement where liked minded souls ultimately came together to do something pointless but fun - or as the New York Times puts it, "mostly young, educated, vanguardish men and women have been countering technologies of control (databases, ubiquitous surveillance, etc.) to turn the crowd, paradoxically, into a forum for idiosyncratic behavior."
The silent discos in London railway stations, the Toys R Us New York flashmob and so on were all good examples of crowds coming together around a single idea, rather than coming together for a purpose.
However, 'Flashmobs' have now well and truly hit the mainstream with executions such as the T-Mobile Liverpool Street flash mob ad or even last week when 21000 people 'flashmob danced' to the Black Eyed Peas in Chicago for the launch of the new Oprah show:
The appeal to advertisers of this sort of execution is obvious. Create a stunt / event to drive the Conversation, use social platforms such as YouTube to distribute to a wider audience and reap the continued benefits of often free traffic (just look at the view counts of the T-Mobile YouTube films....)
However, events in Hamburg yesterday show that 'underground' / non-commercial flash mobs are still effective at drawing attention. Angela Merkel's election speech in Hamburg was hijacked by internet organised crowds who insisted in celebrating every policy announcement with a loud 'Yeah':
Unsure of what to do, the 'Yeah' shouters were allowed to continue throughout the speech. The 'Yeah' shouters do not appear to have been politically motivated but certainly livened up the election campaign. Shows that however commercial flashmobs become, there will always be people interested in using the internet to organise and come together.