Facebook decided on Friday to allow a type of paid political message that had sidestepped many of the social network’s rules governing political ads, in a reversal that highlights difficulties tech companies and regulators have in keeping up with the changing nature of paid political messages.

Facebook’s policy change comes days after the Democratic presidential candidate Mike Bloomberg exploited a loophole to run humorous messages promoting his campaign on the accounts of popular Instagram personalities followed by millions of younger people.

The Bloomberg campaign had paid more than a dozen social media influencers to post Bloomberg memes using their Instagram accounts, each of which has millions of followers.

The memes showed the 78-year-old candidate, in a tongue-in-cheek awkward fashion, chatting with popular social media influencers like “Tank Sinatra”, asking them to help him raise his profile among younger people.

“Can you post a meme that lets everyone know I’m the cool candidate?” Bloomberg wrote in one of the exchanges posted by an account called FuckJerry, which has nearly 15 million followers on Instagram. The candidate then sent a photo of him wearing baggy chino shorts, an orange polo and a zip-up vest.