Zuckerberg and Dorsey to be quizzed by Senate following Biden vote victory

If you follow US tech, you're probably getting a sense of deja vu.Senators are about to grill Twitter's Jack Dorsey and Facebook's Mark Zuckerberg.It's only three weeks since both chief executives testified. But since then the political landscape has wildly altered.It is Democrat voices now, not Republicans, that arguably pose the greatest threat and will be listened to more closely.In particular that of Vice President-elect Kamala Harris, who is a member of the Senate Judiciary Committee - though it's not confirmed whether she'll participate.Labelling TrumpAfter the election, there were fears that social media might fan the flames of chaos, and lead to riots on the streets.Although there were scuffles in Washington on Saturday night, mass unrest has not materialised. Collective sighs of relief have been heard around Silicon Valley. The world - so far - hasn't imploded.But fake news and misinformation around the vote have been rife on both platforms.Twitter and Facebook have labelled misleading content with varying degrees of success.That has put them once again on a collision course with President Trump.Howls of discontent from Republican voices greeted Twitter's repeated labelling of his tweets.Many Republicans are now pushing for people to dump Twitter in exchange for Parler - a "free speech" version of the app.But there's only so much you can do if Twitter decides to suppress, take down and/or label a tweet.You can complain to Twitter or leave the platform, but ultimately Twitter decides what action to take. Twitter owns the platform. If you don't like the rules, too bad.The same goes for Facebook.That's why Republican senators see this as an opportunity to grill Zuckerberg and Dorsey - their first chance since the election - and to blow off some steam.But the two CEOs will be aware it's Joe Biden they must now please.Facebook, in particular, has already been the focus of anger from the President-elect's aides.