Sabastian Wernicke summarizes the facts behind what makes for a popular presentation in this statistics about TED Talks keynote. It's hard to argue with statistics as they are often the bulk of reasoning behind new developments, innovations and practices. According to Wernicke there are key similarities between the TED talks that are hits and those that aren't as popular.
Words like "you, coffee, happiness, brains, girls" are often included within TED Talks that rate very high in popularity. People generally enjoy presentations that center around topics that they can connect with and relate to more easily and deeply. Talks about more technical topics such as architecture, weather or material, while interesting though they may be, generally rate lower in terms of popularity.
How one delivers a speech also has a tremendous impact as to how a talk is received. Presenters who wear glasses, let their hair grow out longer, dress nicer and talk over the allocated time limit do 50 percent better than those who don't. Understanding one's audience and how better to connect with a crowd is crucial in terms of making a positive impression.