Microsoft are to "retire" their instant messenger chat tool, Windows Live Messenger (WLM), and replace it with Skype.
The service will be phased out worldwide by March 2013 except in China, reports the BBC.
Microsoft bought Skype last year for £5.3bn ($8.5bn) and aims to make it the main chat service amongst users.
Writing in a blog post, Skype's president, Tony Bates wrote: "We want to focus our efforts on making things simpler for our users while continuously improving the overall experience."
To make the transfer from WLM to Skype as simple as possible, users will be able to sign in using their old WLM password and username.
Users are also being lured with the promise of support for more devices, such as iPad and Android tablets, screen sharing, group video conferencing and the ability to place calls to landline phones, reports PC Advisor.
At its peak in 2009, WLM (then called MSN) boasted over 330m unique users but since then this number has been falling whilst Skype user numbers have been increasing.
One of the reasons for this is that Skype is now integrated into Facebook, which has 1bn users.
Brian Blau, from the consultancy Gartner, told the BBC: "When a company has competing products that can result in cannibalisation it's often better to focus on a single one.
"Skype's top-up services offer the chance to monetise its users and Microsoft is also looking towards opportunities in the living room.
"Messenger doesn't seem like an appropriate communications platform for TVs or the firm's Xbox console - but Skype does."