Why Microsoft acquired Skype?

The acquisition of Skype by Ebay a couple of years for $2.6Billion was thought to be a bad move and was thought to be overvalued. What changed in a couple of years that made Skype increase in valuation? Is the $8.5Billion valuation of Skype justified?

Few years back Skype was just another messenger connecting people over the internet. Then it introduced video chat and then it introduces call to any phone. But this is not why Skype is valued so high. Skype is now capable of conference video call - mass video conference and twitter and facebook are embedded in. It also supports multiple third party applications within Skype to collaborate more efficiently. Skype is also one of the most used applications in iphone and Android that allows video chat over 3G.

Now how does Microsoft benefit to the tune of 8.5 Billion?
1) Skype is a Unified Communications play. Microsoft was lacking in Video conferencing and Skype would fill this major hole. The mass video conferencing is a great value add for Microsoft. Skype is a decent collaborative tool with screen sharing capability that could rival Cisco's Webex. Microsoft might use Skype's technology in its Lync, Microsoft's UC software.
2) Skype is also a major mobile play with Skype enabling free video chat over wifi and  3G. With Microsoft collaborating with Nokia, Skype could be used innovatively to increase the value of Windows Phone. (Think T mobile's free phone call over wi-fi feature)
3) Skype is also a social play with Facebook and twitter embedded within it. Could it be leveraged as a CRM tool? Possibly.
4) Finally, Microsoft can deliver more ads through Skype - ads on video chat - why not? I could also suggest a neat idea here - the software that analyzes the real time voice and suggest ads (privacy concerns?! whatever..)

What does Skype get out of Microsoft deal?
Skype might become ubiquitous, with presence increasing in all the devices - mobile phones, tablets, internet enabled TVs, Ford sync dashboard.

And who is the competitor for Skype? uh... None! at least none that could rival 145 million monthly user and 25 million simultaneous user!!

So now is it worth $8.5 Billion for Microsoft? Sure in the long term but I definitely think Microsoft should have bargained more over the price!