Twitter's 140-character limit is going away, at least for the private messages you send on the service. As promised, the company said today that it will now allow messages of up to 10,000 characters in its mobile apps, desktop apps, and the web. It will also work in third-party apps, such as Tweetbot, the company says. "It's the No. 1 request we get from folks," said Sachin Agarwal, product manager for DMs, in an interview. "They want to be able to say what's on their mind and be themselves."

After neglecting the feature for years, Twitter began rolling out improvements to direct messages when Kevin Weil took over the product organization last fall. The company restored the ability to send links, added group and photo messaging, and began letting you share tweets natively inside the messages. The idea, Agarwal says, is to make DMs the place where you talk about the stuff you see on Twitter. "We want to make sure you can really fluidly move between public and private," he says. Among other things, removing the 140-character cap on messages make it easier for businesses to conduct customer service over DMs.

"We want to make sure you can really fluidly move between public and private."

Over the years, Twitter has explored releasing a stand-alone messaging app built on DMs, a la Facebook Messenger. I asked Agarwal how he thought about that question today. He wouldn't say anything about unreleased products, but suggested DMs functioned best as a kind of backchannel for Twitter: a place to take discussion of tweets, or the people tweeting them, to a private place.

I wonder if that isn't thinking too small. Twitter's asynchronous nature has made it a place where people often meet new friends, business contacts, even romantic partners. A lightweight messenger app could open up new possibilities for the company, just as it has for Facebook and the Asian mega-messengers. Perhaps that will come down the road. In the meantime, though, you've got a 10,000-character box to fill. Have at it.