I think they'll do it, but not because they see Trump as a threat. They'll do it to prevent "hate speech". Websites that criticize Trump will be signal-boosted, and those that criticize Sanders or Clinton will be suppressed for using "hate speech" and for being "conspiracy nuts", even if their tone is identical to that of Trump's critics.

For the record, I don't care which of these contestants wins. I don't even care about media biases, because I think it's only natural. But I am disappointed when tech companies like Google, Facebook, and Twitter, that are not content creators, but are supposed to be just pipelines for content, exhibit clear biases.

For this particular issue, some people suggest a more benign explanation for the bias[1], and they might be right. But I still suspect some manual tweaking to boost some sites, and suppress others.

[1] http://www.slate.com/articles/technology/future_tense/2015/1...