The Daily Mail, New York Magazine, Slate, the Washington Post (in two separate articles) covered a Cornell paper that analyzes the language and interaction patterns behind successful and unsuccessful attempts to persuade: "Winning arguments: Interaction dynamics and persuasion strategies in good-faith online discussion" by CIS PhD students Chenhao Tan and Vlad Niculae and CIS faculty Cristian Danescu-Niculescu-Mizil and Lillian Lee (to appear in the Proceedings of WWW 2016). As the article notes, "Interestingly, the researchers find that some back-and-forth exchange between participants is a sign of success in convincing someone, but that a lot of it is a sign of failure", or, as the paper notes, "Perhaps while some engagement signals the interest of the [original poster], too much engagement can indicate futile insistence."

As for language, "The researchers find that the factor most linked with successfully persuading someone is using different words than the original posts do - a sign that commentators are bringing in new points of view. They find that longer replies tend to be more convincing, as do arguments that use calmer language."  And good news for the more cautious: "Surprisingly, [the researchers] find that hedging - using language like "it could be the case" - is actually associated with more persuasive arguments. While hedging can signal a weaker point of view, the researchers say that it can also make an argument easier to accept by softening its tone."

The paper can be found at:
http://arxiv.org/pdf/1602.01103v2.pdf

The full news coverage can be found at:
http://www.slate.com/articles/technology/future_tense/2016/02/cornell_research_into_winning_arguments_shows_how_to_win_fights.html
https://www.washingtonpost.com/news/wonk/wp/2016/02/10/how-to-change-someones-mind-according-to-science/
https://www.washingtonpost.com/news/the-intersect/wp/2016/02/11/how-to-win-a-facebook-argument-according-to-science/