Twitter appears to have suspended access to its API, which is used by other platforms to communicate with it. So, if you use a social media manager to access your account rather than the Twitter app or website, you may discover that Twitter is not currently working with it. It's unclear whether the move was intentional, but many experts believe it was.

"My guess is that this is because those third-party apps do not show ads and they allow the user to manage their feed as they see fit, which is at odds with Musk's plans to put more ads in front of users' eyeballs and prioritize the tweets of people who have paid for Twitter Blue," said tech commentator Kate Bevan.

Although Twitter has not made an official announcement, popular apps that appear to be struggling include Tweetbot, Fenix, and Twitterific.

The order in which tweets appear on people's timelines is perhaps the most noticeable change. A new tab allows you to select between the most recent tweets from people you follow and those recommended by Twitter.

If you're using an iPhone, you'll see two columns at the top, "for you" and "following"; if you're using an Android device, you'll see a star icon on the top right-hand side of the screen. The problem is that many users did not notice or were unaware that the app occasionally reverted to Twitter's curated "for you" feed. There have been complaints that this feed is mostly made up of Twitter recommendations and interactions between people you follow and people you don't know, rather than the content you chose to follow in the first place.

Others, on the other hand, don't mind: "Some days I want to go to a restaurant with just my friends, some days I'll pitch up at the pub and see who's in...can be fun," one Twitter user explained.

Mr Musk began with some high-profile accounts that had previously been banned for violating Twitter's rules. They included Ye (rapper Kanye West), who was barred from sharing anti-Semitic posts, influencer Andrew Tate (who is currently being held in Romania on charges of people trafficking), and former US President Donald Trump, whose tweets were accused of inciting the Capitol Hill riots in January 2021.

Twitter's subscription service, Twitter Blue, launched at the end of November after a few false starts. The $8/$11 (£6.50/£9) monthly fee guarantees access to extra features such as an edit button, increased visibility, and fewer ads. Anecdotally, it appears to have attracted a reasonable number of subscribers, but not a large number - though, as usual, no official news about its success has been released thus far.

Twitter's "blue tick," which is now a sign of a subscriber, was previously a symbol of a verified account. It was given to the accounts of hand-picked celebrities, journalists, and brands by Twitter to indicate that they were not fakes.

Those who acquired a blue tick under the old regime still have them, along with a message explaining that it is a "legacy" and "may or may not be notable". As a result, seeing a blue tick next to an account does not automatically confer authority on that account.

It has been replaced by a gold or silver tick for brands and government figures, so Coca-Cola is now gold, with an explanation that it is an "official business," and Rishi Sunak, the UK Prime Minister, now has a silver badge.

Twitter had to change whether Mr. Musk was there or not. Its user base and ad revenue had been stagnant for a long time, while rival social networks had sprung up and experienced explosive growth. Twitter is known for being a small but influential platform, but this was not translating into profits.

Mr. Musk is "a master of PR and spin and innovation and creativity", said social media expert Matt Navarra. He is not afraid of causing a stir or tearing up the rulebook. But will his revolutionary tactics turn around the fortunes of this floundering company, which he claims was losing $4 million per day when he took over?

It's difficult to say because Twitter is secretive about its metrics. It is now a privately owned company, as it should be. However, new advertisers do not appear to be flocking to the site, users are complaining about changes to the way their accounts are displayed, and a recent API change has irritated developers, a community that Twitter needs to help it grow.

Mr. Navarra of his own user experience of engaging with 150,000 followers said, "The vibe seems to have shifted and it doesn't seem to be quite what it was before. I don't see any signs of green shoots for a new Twitter."