Most social networks rely on displaying ads for generating revenue and it forms a huge chunk of their cash flow. They usually move from being backed by venture capitalists into displaying ads which are paid for by brands or individuals. The fact that reports indicate that Twitter is not showing ads at all to a certain subset of users is rather interesting.
According to a report by Recode, Twitter has stopped showing ads to its most prominent users to the point it is nearly ad-free experience. A spokesperson from Twitter, Will Stickney was quoted as saying “We’re constantly looking at constraints and adjustments to optimize which ads are shown and how often.”
Apparently it was a move to keep these popular users engaged on Twitter since as always they generate massive traffic on their accounts, which is good for Twitter. Also, apparently Twitter does not give the ad free treatment to a particular popular person just by their star power but by their volume and tweet reach they generate.
It actually makes sense for Twitter to make such a move because the reason why people login on the platform is to get in touch with what is in the moment and this includes updates from their favourite celebrities. Also in general, adds on Twitter tend to be quite intrusive and can dim the whole experience and if that is a reason some prominent Twitter users are engaging less, it is a good idea to give them an ad free experience. Other speculations could be Twitter could decide to launch an ad free subscription although this could be highly unlikely if they want to retain the 320 million users.