Shashi Tharoor, in the news for tweeting his comments against the new Indian visa rules, has often rocked Twitter with his unusually frank views.

Swine flu
When swine flu was first reported in India, it was all everyone was tweeting about — where to get masks, where to customise them, which hospital to go to for a check up — in short, tweets helped disperse information. The tweets added to the global trend on Twitter around the disease. #swineflu remained a trending topic on Twitter for close to two months.