I don't think Windows Live messagenger is going anywhere -- SKYPE will be OK as MS will use ITS user base and application while quietly "killing off" WLM.
Or they might "re-brand" WLM. Remember there are ZILLIONS of mobile phone and fixed line users who don't use Windows at all --- Macs, Linux systems, smart phones etc etc.
Incidently since the news is now on the BBC website it looks almost "Semi official".
Stuff that appears on the BBC website is usually (or invariably) pretty accurate.
BBC News - Microsoft in talks to buy Skype, report says