chief executive Jack Dorsey has told US lawmakers the company's
algorithms have not always been "impartial".
said the platform "unfairly" reduced the visibility of 600,000 accounts,
including some members of Congress.
he was unable to immediately say whether a majority of them were
Republican, Democratic or otherwise.
Dorsey is being questioned by senators over allegations that Twitter
censors conservative voices.
Republicans, including US President Donald Trump, have accused Twitter
of bias, which the company denies.
does not use political ideology to make any decisions, whether related
to ranking content on our service or how we enforce our rules," said Mr
he said the company had made mistakes.
Wednesday, the US Department of Justice said it would investigate
"growing concern that these companies may be hurting competition and
intentionally stifling the free exchange of ideas on their platforms".
is the Twitter hearing about?
of censorship were fuelled when Twitter added a "quality filter" to the
platform and its search results.
users noticed that their tweets no longer appeared in search results and
suggested that their content was being hidden, known as a "shadow ban".
Dorsey told senators that the platform used "hundreds of signals" to
decide "what to show, down-rank and filter".
do not shadow-ban anyone based on political ideology," he said.
explained that the algorithm had acted on the behaviour of people
following accounts - so some politicians were punished for the behaviour
of their followers.
was unfair", said Mr Dorsey. "We corrected it."
senators in the hearing said the investigation was a waste of time.
Paul Sabanes said the hearing had been triggered by "deep-state
conspiracy theories proffered by the president" while fellow Democrat
Jerry McNerney said it was an effort by Republicans to motivate their
Trump and many Republicans have peddled conspiracy theories about
Twitter and other social media platforms to whip up their base and
fundraise," said Democrat Frank Pallone.
Pallone said Twitter could not be accused of anti-conservative bias
while it allowed President Trump to use it for "juvenile tweets and
else did Mr Dorsey reveal?
Eliot Engel asked why Twitter did not require people to verify their
identity when registering an account. Mr Dorsey said the platform had
systems to detect bots and had prevented half a million fake accounts
from even being used
why Twitter relied on its users to report inappropriate content, Mr
Dorsey said it was a "matter of scale" but that it responded quickly
to reports based on their severity
Pallone asked how many human moderators Twitter had in the US and how
much they were paid. Mr Dorsey was unable to answer
Fred Upton asked how Twitter determined whether somebody was trying to
manipulate a conversation. Mr Dorsey said the platform was focused on
"conversation health", with factors such as "shared attention" taken
whether Twitter's rules were clear, Mr Dorsey said he accepted they
were difficult to understand and needed to be "more approachable"
Adam Kinzinger asked whether Twitter stored user data in Russia. Mr
Dorsey replied that Twitter did not have servers in Russia
Michael Doyle asked explicitly whether Twitter had taken action to
censor conservatives. "No," replied Mr Dorsey