Trump is a massive Twitter fan and uses the site nearly every day, so it's worth noting that he hasn't tweeted since 8.17 am on Wednesday - that's almost 2 days (and counting). This marks the fifth-longest Twitter outage for Trump since he announced his candidacy in June 2015.
In the past, Trump's silence has usually corresponded with periods of slow news. For instance, Trump's longest break from Twitter was over the 2016 Thanksgiving Day weekend.
It's safe to say that the release of ex-FBI Director James Comey's written testimony on Wednesday is certainly playing a part in the President's muteness. Trump hasn't even provided a thorough counter to Comey even after 37 hours of the testimony going before the Senate's Intelligence Committee.