On her new Twitter account, she explained that due to State Dept rules formed during the Obama administration, she was forced to clear her official one and its 1.67 million followers after leaving the Ambassador position.
However, Nikki Haley confused some people by stating that she had to “clear” her account. Former Obama-appointed Homeland Security Department counsel Eric Columbus stated that she merely had to relinquish control of the account for archival purposes.
Graham Lampa on Twitter states that he is a former State Dept official who wrote the policy Haley refers to in her post and hints that Nikki Haley might truly be running for president in 2020:
Quotes from the policy states, “Personnel should be aware that repurposing an existing personal social media account as an official account may subject the account to official clearance procedures and ethics controls[…]” and “[…]the Standards of Conduct prohibit employees from using their official titles, positions, or any authority associated with public offices for private gain.”
Obama was the first president to really use social media as a public figure, and was pioneering this new platform throughout his presidency. When Trump took office, Trump and Obama switched Twitter titles.
We have yet to see if Trump will have to remove his account, as he kept his personal Twitter account even after his presidency. Considering the following he gained due to his role, how this will be handled still seems undecided.
In summary, this policy is to ensure that political figures don’t carry Twitter followers accumulated from high-profile jobs into a new account handle.