SAN FRANCISCO: Brands and agencies have reacted cautiously to Twitter's announcement that it may scrap its 140-character limit, as the social media platform seeks to increase user numbers.

CEO Jack Dorsey observed that Twitter had not started with that character restriction and tweeted (in a screenshot of a text) that "we've spent a lot of time observing what people are doing on Twitter, and we see them taking screenshots of text and tweeting it".

He added that "we're not going to be shy about building more utility and power into Twitter for people".

Many Twitter fans were vehemently opposed to the rumoured idea that users would be able to work with up to 10,000 characters within a few months. Nor were investors impressed, as Twitter shares fell almost 3%.

Re/code was unsure what the changes would mean for Twitter but observed that "expanding the limit is a sign that Twitter and Jack Dorsey are willing to make serious changes in hopes of luring new users".

Whether pushing the platform towards Facebook is the best way of doing so remains an open question. As Mashable pointed out: "There is no guarantee that overhauling a key feature of Twitter will do anything to change how non-users feel about the service."

The suggestion is that the tweets will continue to appear in the current 140-character format, accompanied by a call to action revealing more content.

And that, said Fortune, will lead on to Twitter copying Facebook's Instant Articles and offering to host publishers' content in return for a cut of advertising revenue.

Brands, however, are less likely to be attracted by an extended character count. Gina Roughan, content director at digital agency Zone, remarked that a 2,000-word article on a supermarket wasn't going to get retweeted or drive brand appreciation.

"Finding success for brands on the platform has usually been about offering pithy, timely and funny content – witness the social-media totem that is the now tediously overexposed Oreo Super Bowl tweet – and that won't change," she told Marketing.

Some highly regulated categories, however, will welcome the longer format that will make it easier to meet disclosure requirements, including the pharmaceutical, alcohol and healthcare industries, as well as financial institutions.

Data sourced from Twitter, Marketing, Fortune, Re/code, Mashable, Adweek; additional content by Warc staff