Nate Silver explains why Donald Trump continues to do well in the polls

It's the media attention baby:

Earlier this month, I outlined Donald Trump’s “Six Stages of Doom” — the hurdles he’ll have to clear to win the Republican nomination. The first obstacle: Could Trump keep his polling numbers up when another storyline emerged that prevented him from monopolizing the news cycle? “For a variety of reasons, Trump isn’t affected much by negative media coverage — it may even help him,” I wrote. “But a lack of media coverage might be a different story.”
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The share of news coverage devoted to Trump has been fairly steady over the past month. Steady and very high, at 50 percent to 60 percent of all coverage received by the GOP field. In other words, Trump is getting as much coverage as the rest of the Republican field combined. But Trump’s Google search traffic is often just as high, or higher.
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What’s interesting is how Trump seemed to go out of his way after the debate to ensure that he’d remain the center of attention, with his tirade against Fox News anchor Megyn Kelly (a feud that he’s since resurrected). That tended to drown out most of the coverage of whether, say, Fiorina or Kasich had gained momentum after the debate, perhaps preventing them from having the sort of feedback loop of favorable attention that can sometimes trigger surges in the polls.

I don’t know whether this was a deliberate strategy on Trump’s behalf. But if so, it’s pretty brilliant. Trump is perhaps the world’s greatest troll, someone who is amazingly skilled at disrupting the conversation by any means necessary, including by drawing negative, tsk-tsking attention to himself. In the current, “free-for-all” phase of the campaign — when there are 17 candidates and you need only 20 percent or so of the vote to have the plurality in GOP polls — this may be a smart approach. If your goal is to stay at the center of attention rather than necessarily to win the nomination, it’s worth making one friend for every three enemies, provided that those friends tell some pollster that they’d hypothetically vote for you.