538 has an interesting data visualization up, showing where the various candidates have the most Facebook likes. Nationally, Ben Carson is in the lead. I guess every Adventist in America has liked his page.
Obviously, he’s not going to win the nomination that way, but it’s an insight into why he hasn’t dropped out of the race yet. He still has his very passionate supporters, and he probably hears lots of positive things from them.
Earlier in the race, Carson and Trump were seen as similar candidates: outsiders with intense “tribal” support. And that is still true, but the tribe that’s backing Trump — the white working class, basically — happens to be enormous.