After exploring several websites, I believe that it is true that Swift's post drove lots of people to vote.gov, but that a lot of the articles give different numbers. Also lots of social media posts have misinterpreted what those numbers mean.
On Tuesday, Sept. 10 a presidential debate between Harris and Trump took place. Swift announced her support for Harris in an instagram post following the debate. She later posted a instagram story that included a link for followers that directed them to vote.gov. Vote.gov is not a website where citizens can actually register to vote. It is a website that directs individuals to their state's election website, so they can learn how to register in their state.
Many social media posts have misinterpreted the variety of numbers being reported by news outlets as a tally of new voter registrations. But that is NOT what those numbers mean. Those numbers are just how many people clicked on the link and where taken to the vote.gov site. Another pattern I am seeing is a variety of numbers. For example, NPR is reporting "In the 24-hour window that Swift's story was live on Instagram, a GSA spokesperson told NPR that there had been 405,999 visitors to the Vote.gov website via her unique link," but CNBC is reporting "Taylor Swift’s endorsement of Vice President Kamala Harris in a Tuesday night Instagram post drove at least 337,826 visitors to Vote.gov, a government website that directs users to state-specific voting information, a spokesperson for the U.S. General Services Administration told CNBC.
I left a voicemail and reached out to GSA by email on Sept. 26. I have not heard back, but if I do, I will update this post to confirm or deny the numbers being reported.