Even Team Trump has shifted to the network after Twitter founder Jack Dorsey decided to hide the US president's tweet during the Minneapolis protests. Trump's son Eric Trump and Trump's campaign manager Brad Parscale both have accounts.
"It comes in the immediate wake, of course, of Twitter slapping some 'interstitials' – warnings and fact checks – on Trump's tweets," says Carl Miller, the research director at the Centre for the Analysis of Social Media.
"That itself was part of a years-long dispute where the American right has felt that they've been subject to censorship by Californian big tech."
Parler, which was established by 27-year old John Matze in 2018, defiantly bills itself as a Twitter alternative. In an interview with Forbes, Matze claimed
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that Parler now has 1.7 million users, almost double its supposed April tally.
The app has revelled in the furore directed towards mainstream social networks – and Matze believes it will only become more popular as the social media giants deliberate over their own policies.
"No one is going to want to stay on Twitter if the conservatives are gone," he told CNBC.
The site prides itself on allowing users to "speak freely" and is against the use of fact-checkers.
Users can post much in the same way other as they do on Twitter and Facebook. They can "echo" posts they wish to share with their own followers. Alternatively "upvoting" takes the place of traditional "likes".
Executive director at the Open Rights Group Jim Killock says the app is "filling a space" created by the restraints.
"It may be reasonable for these platforms to make such restraints, but it does point to the dangers of pushing far right speech into highly networked but entirely closed spaces," he says.
"If the pursuit of an ever safer online environment means that trolls and extremists congregate in special, uncensored spaces and wind each other up with nearly nobody to challenge them, then we may be creating a more risky online environment rather than less."
With its free speech policies, Parler has become a hotbed for extremist views and conspiracy theories. It has hundreds of posts under the hashtag 'Nazi' as well as more alleging that 5G had accelerated the spread of the coronavirus.
The US dominates traffic to Parler with 87pc of all users from there. But the UK is second only to it with 2.44pc of its audience, according to figures from SimilarWeb. The online stats site says the UK's proportion of Parler traffic has surged 265pc over the past month.
Despite the increase, Miller believes it is still some way off representing any meaningful amount of the British population.
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"In general the online harms versus free speech dispute has simply been a less partisan issue in the UK, and I'm not aware of the same kind of enforcement activity being directed at UK MPs," he says.
"It's just a few clicks to join any of these platforms; the real shift will be when significant resources, money and time are spent on alt-tech by campaigns – and I haven't seen any of that yet."
Despite the "free speech" marketing of Parler, the company does impose some rules. It advises users "not to use language or visuals which suggest people should die".
It also advises users not to use language that suggests people "should be attacked".
Under these guidelines, one would imagine that Trump's tweet suggesting "when the looting starts, the shooting starts" would be taken down even on Parler.
Parler did not respond to a request for comment at the time of writing.
Some reports in the US suggest that the president anticipates being banned from Twitter eventually and that he may move to another platform.
Such a move would dramatically shape the outcome of the US election and represent a watershed moment in the digital war over online censorship.
For now, however, Trump is sticking to Twitter where he still has a direct line to his more than 82.5 million followers.
