Twitter's privacy policy, which calls for tweets to be deleted from its system after a user deletes them, may have kept useful data out of the hands of investigators probing Russia's meddling in the 2016 presidential election. 

The information could have been used to determine how Russian operatives “were trying to nudge the narrative in a certain direction,” according to a report by Politico, which cited unnamed cybersecurity pros. 

"So if you have access to all this, you can basically see when botnets appeared and disappeared, and how they shaped narrative around certain events,” said the report, quoting an analyst.

Twitter's practices mean it doesn't "know who is on their platform, or how bad people are doing bad things," Politico quoted Clint Watts, a former FBI agent, as saying.