It looks like Twitter may be the next in line to try and take a piece of the instant messaging game, according to AllThingsD. Word on the street is that Twitter is testing a standalone direct message app that may up their game a bit. Twitter started rolling out the ability for users to receive DMs from people whom they don't follow earlier this week, so this could be the next step if things go well.
The rumored service is not unlike that of Facebook Messenger as it would be a separate, standalone app from Twitter. Currently Facebook Messenger allows users to chat within the Facebook app from the web or any mobile platform, or via the Facebook Messenger app.
While people have been using Twitter for this type of communication for years, this would mean that Twitter could serve as a replacement for other instant messaging apps as users wouldn't have to follow each other to send or receive direct messages. It's rumored that Twitter also met with employees from MessageMe earlier this year.
It's still just a rumor at this point so there's no telling yet if the service will come to be. With users having already adopted other services like BBM or WhatsApp, who knows if Twitter could catch on the same way. We already know that WhatsApp has a huge userbase, but as we've seen, BBM could be even bigger on other platforms when it goes live.