Why do some politicians actively use social media, while others lag behind? To answer this question, we propose that opposing party politicians, underdogs, and extremists are more likely to become active political tweeters. Research has shown that media attention is generally concentrated on politicians with power; that is, ruling parties and party leaders. We thus hypothesize that politicians marginalized from media attention, namely backbenchers and those from opposing parties, may perceive greater potential benefits from social media. Further, politicians whose ideological positions do not match well with those of major news media (i.e., extremists) may perceive risks in facing tough questions from journalists, as well as the media's gatekeeping process. We thus hypothesize that extremists may perceive greater benefits from using social media, because they can control their message. We tested these hypotheses using data on U.S. Senators’ public communication activities on Twitter and in press releases in 2009–2011 and found strong support.

中文翻译：

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政客为什么发推文？极端主义者，弱者和反对党为政治高音

为什么有些政客积极使用社交媒体，而另一些却落后呢？为了回答这个问题，我们建议反对党的政客，弱者和极端主义者更有可能成为活跃的政治高音喇叭。研究表明，媒体的注意力通常集中在有权力的政治家身上；就是执政党和政党领袖。因此，我们假设，政治家因媒体关注而被边缘化，即后座议员和反对党的政治家可能会从社交媒体中获得更大的潜在利益。此外，其思想立场与主要新闻媒体（即极端主义者）的意识形态不符的政治家可能会面临面临记者的棘手问题以及媒体守门程序的风险。因此，我们假设极端主义者可能会从使用社交媒体中获得更大的收益，因为他们可以控制自己的信息。我们使用美国参议员在Twitter上的公共交流活动以及2009-2011年的新闻稿中的数据检验了这些假设，并获得了有力支持。