Twitter, the micro-blogging site started in 2006 by Jack Dorsey, sees roughly 5 billion tweets every month, according to the company.� It's a social circle that has advertisers giddy with possibility, sparking talk of sky-high valuations in Wall Street and secondary market circles. What makes Twitter so popular is simple: people tweeting.� The following is a list of the 10 most recent world-breaking moments on Twitter, as measured in tweets per second.