From TechCrunch report we know the story behind eBay-Skype.
Skype software base on an engine call Global Index own by Joltid, but Skype does not have the right to access Global Index source code, but Joltid license GI source code to Joost, the online web TV. GI is a peer to peer software which Skype base on to make Internet voice call.
Finally we know why Skype was not improved for pass few years, because Skype don't even own their core technologies.
I have a different view point on this. Skype has improve a lot in their software and service since the day I have registered, it still improving after eBay has bought it. May be it is just not good enough.
Other than voice and message, Skype has SkypeIn, SkypeOut (online number), SMS, call forwarding service. It was available on many platform like Windows, Mac, Linux, Windows Mobile, iPhone...
I am not sure why eBay bought Skype, may be just for the user base, so the core technology is not really important to them. I am sure eBay knows what they are getting, just found out that is a bad investment after few years time, eBay management team should be responsible for it.
May be Skype just lack of an innovative leader. Why eBay make such a mistake that to acquire Skype without their core technology? May be just because eBay is not good at software business? If eBay sell Skype, this is good for users like us, because this piece of software could be ruin in eBay's hand.