If Twit­ter offi­cial­ly extends the tweet’s max­i­mum char­ac­ter count, it would mark the biggest change in the social network’s his­to­ry and the biggest bet on its future.

Twitter’s defin­ing fea­ture — the tweet’s 140-char­ac­ter lim­it — may soon go the way of Instagram’s square posts and Vine’s, well, every­thing.

Twit­ter has start­ed a test to dou­ble the length of tweets to 280 char­ac­ters, the com­pa­ny announced on Tues­day.

Twit­ter will use the open-end­ed test to decide whether to offi­cial­ly change the max­i­mum tweet length, but the com­pa­ny has not yet com­mit­ted to that change. If Twit­ter does opt to offi­cial­ly adopt 280 char­ac­ters as the new max­i­mum length, it would mark the biggest change to the social net­work since its found­ing in 2006 and the biggest big bet yet by the com­pa­ny to increase its user base.

Begin­ning today, peo­ple may start to see these twice-as-long tweets in their Twit­ter feeds, though the option to post 280-char­ac­ter tweets will be lim­it­ed to “a small group” dur­ing the the test­ing phase, accord­ing to a com­pa­ny blog post pub­lished by Twit­ter prod­uct man­ag­er Aliza Rosen and senior soft­ware engi­neer Ikuhi­ro Ihara. Those extend­ed tweets could include ads if mem­bers of the test group opt to run a 141-char­ac­ter-plus tweet as a Pro­mot­ed Tweet, said a Twit­ter spokesper­son.

The test will span all lan­guages except Chi­nese, Japan­ese and Kore­an, because in those three lan­guages, a sin­gle char­ac­ter can com­mu­ni­cate twice as much infor­ma­tion as a char­ac­ter in oth­er lan­guages, per the blog post.

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. 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,” wrote Rosen and Ihara.

Aside from the length­ened char­ac­ter count, Twit­ter is not mak­ing any oth­er changes to the length of tweets or how they are count­ed. But Twit­ter has made a lot of changes on that front in the past year. Last year, the com­pa­ny stopped count­ing pho­tos, videos, GIFs, polls and quot­ed tweets against the 140-char­ac­ter lim­it, though links still count. Then, ear­li­er this year, it dropped user­names from the char­ac­ter count in reply tweets (all of these changes will apply to the 280-char­ac­ter tweets being test­ed, per the spokesper­son). And now, the com­pa­ny may cap those changes by offi­cial­ly chang­ing the count itself.

Twitter’s 140-char­ac­ter lim­it was orig­i­nal­ly imposed to approx­i­mate the length of a text mes­sage and make the social net­work more invit­ing to peo­ple to post thoughts on the fly from their phones. “Every­one gets the same amount of space to Twit­ter, no more con­fu­sion or guess­ing as you are typ­ing,” wrote Twit­ter co-founder and cur­rent CEO Jack Dorsey in a note to employ­ees in Jan­u­ary 2007, accord­ing to the book “Hatch­ing Twit­ter.”

But what was meant to mit­i­gate con­fu­sion has elicit­ed frus­tra­tion over the past decade. Appar­ent­ly, peo­ple do not like to be edit­ed. As a result, they have opt­ed for loop­holes, like tak­ing screen­shots of longer texts typed in their phone’s note-tak­ing app and post­ing them as pho­tos to Twit­ter or string­ing togeth­er mul­ti­ple tweets into a thread, or “tweet­storm.” Or they have cho­sen not to use Twit­ter alto­geth­er, con­tribut­ing to the company’s strug­gle to grow its audi­ence, which had begun to abate but is stag­nat­ing again.

By relax­ing the max­i­mum length of a tweet, Twit­ter would hope to make itself more invit­ing to peo­ple pre­vi­ous­ly frus­trat­ed by its forced brevi­ty but could risk alien­at­ing oth­ers for whom that brevi­ty makes their feeds more eas­i­ly scannable. The del­i­cate bal­ance between risk and reward sug­gests why Twit­ter has not com­mit­ted to the change. Instead, the com­pa­ny will use the test to see how peo­ple respond to see­ing longer tweets and how the option to write longer affects the length of a typ­i­cal tweet.