Twitter's elimination of "locked" accounts from public follower counts has resulted in a decline for users including millions for celebs like Katy Perry, Justin Bieber, Barack Obama, Taylor Swift and Lady Gaga.
One of the biggest losers was Twitter's own primary account (@Twitter), which shed 7.5 million fake accounts to drop 12 percent on Thursday, from 62.85 million in the morning to 55.35 million by mid afternoon.
By comparison, the decline of other large accounts has been smaller.
The 100 most-followed Twitter accounts saw an average drop in followers of 2 percent on Thursday, according to social-analytics firm Keyhole, with a median decline of 734,000 followers.
Singer Katy Perry, who has the most-followed account on Twitter, lost 2.8 million followers through early Friday, dropping 2.6 percent to 106.8 million followers.
Follower counts for Justin Bieber and Rihanna fell 2.5 percent, Ellen DeGeneres dropped 2.6 percent, Taylor Swift fell 2.7 percent and Lady Gaga declined 3.2 percent.
Barack Obama's (@barackobama) total followers shrank by 2.36 million or 2.3 percent to 101.3 million by Friday morning.
Meanwhile, Donald Trump (@realDonaldTrump), possibly Twitter's most controversial major user, saw his follower count drop by about 300,000, from 53.4 million to 53.1 million, on Thursday.
On Wednesday, Twitter said it was making the change in order to boost the credibility of follower-count numbers and improve transparency.
The change in follower counts doesn't affect the active user totals Twitter tracks and reports on a quarterly basis to investors, according to the company.
The majority of Twitter users will see a reduction of four followers or fewer but those with larger follower counts will see a bigger drop, the company said.