Updated

Facebook wasn't the only internet platform that had its data harvested by researcher Aleksandr Kogan. Twitter also sold data access to Kogan in 2015, but the information harvested only dealt with public tweets, nothing private.

According to Twitter, Kogan's firm Global Science Research had one-time access to a "random sample of public Tweets" for a five-month period from Dec. 2014 to April 2015. "We conducted our own internal review and did not find any access to private data about people who use Twitter," the company said in an email.

Twitter also noted that the social media service "is public by its nature." For instance, anyone can search for past tweets across the platform. However, developer access can help companies or researchers filter tweets to better pinpoint when certain topics are mentioned or what's being liked.

Why did Kogan seek out the data? In an email, Kogan told PCMag that he did buy access to the Twitter data, but said it had nothing to do with Cambridge Analytica, which bought Facebook data from Kogan. As many as 87 million Facebook users may have had their data harvested by Kogan for the purpose of political targeting (although Cambridge Analytica disputes that number).

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Kogan said he sought out the Twitter data for the more mundane purpose of helping big brands reach out to customers. "Like if you are Coca-Cola, how many people have tweets about you total? What are some other properties we can learn from the tweets —e.g. average sentiment, maybe some of the geographic spread, etc," he said.

The Twitter data was going to be used in two products for Global Science Research. However, both products "ended up not going anywhere sadly," he said. "No raw Twitter data for any user was ever going to be exposed to anyone, nor any identifiable information."

On Monday, Cambridge Analytica also said that it had "never received Twitter data" from Kogan.