After 17 years with an iconic blue bird that came to symbolize the broadcasting of ideas to the world, billionaire Elon Musk renamed Twitter as X and unveiled a new logo, marking a focus on building an "everything app."

On Monday, a stylized white X on a black background became the new logo on Twitter's website, though the blue bird was still seen on the mobile app.

Since taking over Twitter in October, Musk has said he envisions an app that could offer a variety of services to users beyond social media, such as peer-to-peer payments, an idea that mirrors the widely popular WeChat app in China.

The transformation is more simply a way for Musk to make his mark on the company, said Tom Morton, global chief strategy officer at ad agency R/GA. "Twitter's changing name and logo has nothing to do with user, advertiser, or market issues. It's a symbol that Twitter is Elon Musk's personal property.

"He conquered the castle, now he's flying his own flag."

The new logo garnered mixed reactions from users and sparked confusion about what tweets would now be called, while marketing and branding experts said the rebrand risked throwing away years of Twitter's name recognition.

"#GoodbyeTwitter" was trending on the platform on Monday with reference to the old logo as some users criticized the new one.

Musk tweeted on Saturday that "soon we shall bid adieu to the Twitter brand and, gradually, all the birds".