For many of today's computer - and smartphone - users, life without instant messaging of one sort or another is unthinkable.

But back in the late 1990s, when Microsoft bundled an instant messaging and a live audio calls and conferencing service with Windows, the idea of instant, person to person messaging, was a novelty. While the USA had something that approximated to the internet we now know, the rest of the world had fragmented and unreliable connectivity. For text only, the arcane (and still, to many, impenetrable) Internet Relay Chat (IRC) was there for the technically brave and savvy and CompuServe and AoL (with CompuServe being dominant in Europe, AoL in the USA) provided proprietary platforms on a paid subscription model. Microsoft's entry provided free voice and messaging comms indiscriminately to all users of its operating system which, as it bid for world domination, meant almost everyone with a PC - including those with illegal copies.

Over time, other instant messaging services from Yahoo!, Google and many more have taken huge slices of the market and they have added voice and video comms, too. Upstart Skype, which effectively kick-started the internet phone boom, racked up market share first by being easy to use - and appealing to early adopters - became so ubiquitous that its name became a verb. When Skype added instant messaging and file transfer to its repertoire, it became a comms medium of choice for many, including businesses. It's always been difficult to see where the revenue comes from for a free comms platform: Skype generated revenue from its ability to connect to landlines and mobiles over the PSTN and mobile networks, long before smartphones could be used for internet calls.

There are dozens of alternatives for instant messaging, within closed systems: open source content management system Drupal has an excellent service that integrates fully within its products; elearning platform Moodle has an effective but clunky and slow service. The difference between these systems and the others mentioned is that a company hosts the service on its own servers - and therefore has control over the data.

Google has its own Google Voice with IM and also includes IM within Google + and Facebook has both chat and messaging built within the platform. And hundreds of dating sites, blogs and bulletin boards use IM within their closed systems.

When Skype was bought by ebay, the theory was that it would sit alongside ebay's recently acquired cashcow, PayPal. But it was not an easy relationship and Skype passed to Microsoft.

Since then, Microsoft has worked hard to improve the Skype product and, on balance, has done a good job although its performance on some Android devices is widely - and justifiably - criticised. Even so, as a cross-platform product with similar (but frustratingly not identical) interfaces across devices, it has consolidated its position as the stand-alone comms platform of choice for tens of millions. MSN Live Messenger, despite its long life, is becoming sidelined. Rather than wait for it to die a lingering death, Microsoft has acted to kill it.

But users will not be orphaned. According to an entry on the Skype blog yesterday, "Skype and Messenger are coming together. Millions of Messenger users will be able to reach their Messenger friends on Skype. By updating to Skype, Messenger users can instant message and video call their Messenger friends."

Microsoft's history with Skype has been far better than its critics suggest. There have been some serious outages, some programming mistakes that have led to both connectivity and data problems and other hiccups but, underneath it, the improvements have been aimed at - and have broadly delivered - a more coherent and more stable platform. Readers of these pages will know that this newspaper is no fan of Microsoft's practices or its products and so praise is genuine, not fan boy or PR-placed nonsense.

But MS does need to make money from the "free" platform and to do that it is moving to advertising. That is a cause of annoyance, but it's the same annoyance that users of Google's YouTube have and it makes no difference: the ads are still there, disrupting the attention of users.

But there are concerns: many people separate out their lives - Messenger for certain aspects of their social lives, Skype for family and/or business connections. Integrating the two will mean either maintaining two discrete accounts - or migrating the social life to an alternative provider.

Already, responses on the Skype blog are arguing that there are privacy, security and convenience concerns with users saying that they do not want an integrated account. Those complaints will go unheeded, as have complaints to Facebook about e.g. the forced change to TimeLine and the "visible by default" settings that cause privacy and security worries there.

There is a huge technical difference between Skype and Microsoft's messaging service. Skype is a peer to peer service (the tech behind it was developed by the people who invented peer to peer music sharing) but, right from its earliest days, Microsoft's own platform has been running on Microsoft's own servers.

Other criticisms are the possible loss of free group calls: under Messenger, right from the early days, group calls were part of the service. But under Skype, they are a chargeable option.

Skype has published on its blog (http://blogs.skype.com/en/2012...) graphics of the new system in operation.

And it's piggybacking on the popularity of Facebook, trumpeting the ability to have video calls with your Facebook "friends."

There are some concerns: like Google has merged all its services for a single user under a single account (which leads to a number of account security issues especially for those with a commercial relationship with Google such as AdWords and AdSense) Microsoft is merging the services under a single log-in. It says that Messenger users should "On the sign in screen, select the option to sign in with your Microsoft account. You will be asked if you are already using Skype or are a new user." When that's done, users will be asked to identify both accounts and then to" merge" them. After merger, users should "use your Microsoft account [name] to sign in to Skype."

There is an option to cancel and change the account.

What Microsoft is not saying is what will happen to chat history.

But the screenshots are clear about one thing: when users try to sign into Messenger, once the change is implemented, they will not be able to access Messenger at all: it's going to be the Skype way or the highway.