Page views are not votes, of course, but they could have some predictive power. In each of the first five Republican contests in 2012, the candidate whose Wikipedia page received the most views on voting day (but before winners were announced) also got the most votes. The pattern was not as strong in 2008, when two candidates drew outsize attention, garnering the most page views even on days when they got fewer votes: One was Ron Paul, the other, Barack Obama.

Every Night Is Debate Night

While most readers will not notice every edit, each article is a palimpsest of added or deleted nuggets, often several in a single day, which are archived under the “view history” tab. Some are crude or juvenile smears that are quickly removed by hawk-eyed contributors on the lookout for pranks.

On Sept. 19, for example, the name of Ted Cruz’s spouse was changed to “Edward McMahon,” then changed back to “Heidi Nelson” six minutes later.

But other edits reflect substantive disputes that are often debated on Wikipedia’s discussion pages (the “talk” tabs) before they make it to the pages of newspapers, mainstream blogs and TV shows.

Mr. Cruz’s birthplace — Calgary, Alberta — became a major issue last month after Mr. Trump questioned whether his rival would be eligible for the presidency. But mentions of his Canadian birth have been added to, modified or deleted from the page at least 636 times dating back to before Mr. Cruz had even run for the Senate. Eventually, the fact led the second paragraph of Mr. Cruz’s entry. (You can view a time-lapse progression of edits to any Wikipedia page on this website.)

Until recently, the struggles with drug addiction of Jeb Bush’s daughter, too, were not widely covered in the news media out of deference to the family’s private struggles. But, on Wikipedia, details of those struggles had been added or deleted at least 90 times over many years.