In front of an audience of hundreds of thousands on the National Mall in Washington DC, and million on television across America and around the world, Donald Trump was inaugurated as president at noon on Friday.
Almost instantly, the White House website was taken over by the Trump team, refreshing to show the detail of the 45th president's plans for the country.
The official presidential Twitter handle was also taken over, with cleared of all of President Obama's previous tweets, which now appear under the Twitter handle .
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The internet reacts to Donald Trump’s inaugural address
President Trump's first official tweet via the @POTUS account, with over 5 million followers, was a Facebook link to the president's inaugural address.
Through his , with 20 million followers, Mr Trump tweeted several select lines from his speech.
Twitter is expected to be an important and unconventional communication tool for the incoming president.
“Trump throughout the campaign and the transition has been able to use Twitter to devastating effect,” Dougal Robinson with Sydney’s US Studies Centre .
“He’s been able to upend the debate on any given issue or policy with a single tweet,” he said.
“We can expect more Twitter and fewer press conferences from Trump as president.”
President Obama's final tweet from the official handle, now moved to @POTUS44, was a message to his supporters.
President Obama has said he will remain active in public life, and will remain in Washington D.C. while his daughter finishes school.