It looks like Snapchat and the enhanced DM of Twitter have some competition from Instagram Direct,Freshly-launched by the Facebook-owned Instagram, it aims to take a chunk of a growing market, private messaging, pushing Instagram into the realm of communication tool rather than simply photo and video sharing. The idea is simple - a select group of friends can send imagery privately whilst carrying on a conversation via text.A new Direct icon allows you to enter into the game. Tap to see an inbox where media has been sent to you privately. Alternatively, create an image or video as usual, then when it is time to 'share', go for the option of sending only to specific people directly. You can send up to 15. After that, you can watch the conversation develop (or not).You can only 'Direct' with people who follow you. If they don't, you'll get a request to follow, which you can confirm or ignore. Once you confirm, they can share with you too.It sounds a winner. Try it out yourself if you have an iOS or Android phone and let us know what you think. No Windows Phone as yet, but that is likely to follow.