Overseas users are puzzled by 'Twitter Circle Penetration' that displays private tweets as recommendations

From around April 7, 2023, there have been a series of reports on Twitter that tweets that should have been displayed only to a limited number of users have been made public.

Twitter Circle tweets are not that private anymore | TechCrunch
https://techcrunch.com/2023/04/10/twitter-circle-bug-not-private/

Many Twitter users have reported a bug in which tweets posted to the ' Twitter Circle ', which shares tweets only in small groups, are leaked to the outside.

According to user reports, tweets posted to Twitter circles are displayed in the 'recommended' section of the timeline.

Mr. Ian Coldwater made a Twitter circle of only one person as a trial and posted a tweet saying 'Please like if you can see this', it seems that two users who Ian does not follow have liked it . This was contrary to the specification that 'tweets posted to the Twitter circle can only be seen by those who participated in the Twitter circle'.

I made a Twitter Circle with one person in it and posted this tweet for science. This was the result. Two people I don't follow saw the tweet & liked it. One of those people doesn't follow me either.

Twitter Circles aren't private. Don't post anything you want private in them.pic.twitter.com/p5uzlmIkuJ

— Ian Coldwater ?????????? (@IanColdwater) April 10, 2023

Even in Japan, the keyword 'circle penetration' was temporarily trending.

When I opened the trend of penetrating the circle, someone I really didn't know was penetrating pic.twitter.com/GTS93UsmIS

— Sᴜᴋᴇᴋᴏ2 (@SUKEKO_22) April 7, 2023

In addition, there was a series of information that the tweet of 'key plaque' was displayed as a recommendation, so 'key plaque penetration' also entered the trend.

Finally, 'Penetration of key plaque' appears in the trend!

…Well, for those of you who don't know, there are times when tweets from people you don't follow (which you shouldn't be able to see) appear in the recommended tab. Speaking of which, it seems that there was a story that it penetrates blocks as well. Circles can be dangerous too. pic.twitter.com/DvAY1V307d

— Yooyoo (@Yooyoo_spl2) April 7, 2023

Former Twitch engineer Theo Browne hypothesized that the 'recommended' algorithm wasn't filtering private tweets well enough, and said, 'Twitter is a total failure at managing content.' In addition, Twitter has released the source code for 'Recommendation', and we will get feedback and improve the algorithm.

Twitter open-sources and publishes the post selection algorithm of the 'recommended' timeline, anyone can download it-GIGAZINE