In 2015, Twitter sold data to Aleksandr Kogan, the researcher who resold Facebook data to Cambridge Analytica. According to Twitter, Kogan did not abuse the data as it did with Facebook.
It is unknown where Kogan wanted to use the data. The researcher obtained access to data from up to 87 million Facebook users by creating a quiz requesting permission to store data from users and their contacts. Hundreds of thousands of people allowed that.
It is possible that Kogan wanted to supply a more complete dataset, for example to Cambridge Analytica, by linking information from Facebook and Twitter. Kogan and Cambridge Analytics have not yet responded to Twitter’s confirmation. Cambridge Analytica used the information to deliver more targeted ads to Facebook users during elections.