"This is a small change, but a big move for us," he wrote, calling the previous limit was an "arbitrary choice.

"Proud of how thoughtful the team has been in solving a real problem people have when trying to tweet," Dorsey added.

A "small group" of users will see the new limits before Twitter decides on rolling out the changes more broadly, the company said.

"Trying to cram your thoughts into a tweet -- we've all been there, and it's a pain," product manager Aliza Rosen and software engineer Ikuhiro Ihara said in a blog post.

"We're doing something new: we're going to try out a longer limit, 280 characters, in languages impacted by cramming."

Twitter planned to leave the old limit in place for tweets in Japanese, Chinese and Korean because internal data showed written characters in those languages packed plenty into the allotted space.

"Our research shows us that the character limit is a major cause of frustration for people tweeting in English, but it is not for those tweeting in Japanese," Rosen and Ihara said.

"Also, in all markets, when people don't have to cram their thoughts into 140 characters and actually have some to spare, we see more people tweeting."

Its growth has failed to keep pace with social network leader Facebook, which has some two billion users, and Facebook-owned Instagram, with 800 million.

 'Making it easier'

"We're hoping fewer tweets run into the character limit, which should make it easier for everyone to tweet," Rosen and Ihara said in the blog post.

"We understand since many of you have been tweeting for years, there may be an emotional attachment to 140 characters... But we tried this, saw the power of what it will do, and fell in love with this new, still brief, constraint."

Twitter has been seeking to draw in users by offering more video, including live streaming of sporting events, aiming to broaden its appeal.

"More is better; no doubt," Gartner analyst Brian Blau said of expanding room in tweets.

"It is still not a lot of content, but you can put a lot in there."

Reaction on Twitter was mixed, with some lobbying for the original cap and the pressure it applied to succinctly express thoughts.

"The 280-character limit is a terrible idea," New York Times television critic James Poniewozik said in a Twitter post retweeted 12,000 times and liked 30,000 times in a matter of hours.

"The whole beauty of Twitter is that it forces you to express your ideas concisely."

Analyst Jan Dawson of Jackdaw Research fired off a tweet saying: "Worried that we'll lose the inherent glanceability of the vast majority of 140-character tweets. More importantly, not the fix Twitter needs."

Many others on Twitter welcomed the news and said raising the character cap was long overdue. Some people already resort to long strings of rapid-fire tweets, known as "Twitter storms," to string together lengthy comment.

Looking like Facebook?

The messaging platform reported a net loss of $116 million in the second quarter, slightly wider than its $107 million loss a year ago.

It remained an open question whether the new tweet limit would ignite the growth an engagement Twitter needs to compete in the fast-moving social media segment.

"The more they expand, the more they start looking like Facebook," Enderle Group analyst Rob Enderle said of Twitter.

"And if they start looking like Facebook, then Facebook will take them out and has the war chest for it."

The move by Twitter could also be rendered moot by lifestyle changes brought about by trends in voice-commanded digital assistants and looking at the world through mixed-reality glasses, according to Gartner analyst Blau.

"What are tweets in those worlds?" Blau said. "We see Twitter sort of struggling to get this business right while everyone else is moving in a another direction."

-AFP