Twitter's filing states that approximately 8.5% of all accounts are updated "without any discernible additional user-initiated action." A Twitter spokesperson tells Valleywag these 23 million accounts largely consist of users who read tweets through third-party apps like Flipboard—depriving the company of any revenue associated with those users.
To be clear, automated accounts aren't necessarily spam accounts, which according to Twitter make up less than 5% of [monthly active users]. Bots can be useful, even essential, accounts for many Twitter users. But once they're set up, they don't usually have any humans behind them, which matters greatly to advertisers who are interested in reaching potential customers. They also don't receive the ads that are shown on Twitter's own properties. And if advertisers are concerned, Twitter and its shareholders should be, too.
Twitter is notoriously cagey with their bot data. A Twitter spokesperson declined to tell us exactly how many bots are automatically tweeting. However, it has been suggested that the number of bots, including automated RSS feeds, content aggregators, and joke accounts, could be in excess of 20 million.
This post and its headline have been updated to clarify the nature of the automated accounts.