It is already known that Skype is popular not only for ordinary users.
It is increasingly penetrating the corporate sector. Even giants like Alcatel-Lucent are partially switching to Skype telephony.
Last week, at our company (telecom daughter, Germany), the authorities decided to put Skype to all those who should be called to different countries. Only under pressure from the chief, the IT department set up and opened ports, strongly resisted under the pretext of security :)
So Skype gains strength precisely in the segment where big money is found, offers what is needed - these are conferences, video.
I do not see unfortunately alternatives. And regret that:
1) Monopolism is always bad, first capture the market, then freely dictate prices
2) Closed protocols, which does not contribute to the very same security policy
Real alternatives - jabber, but where is he in corporate? It remains the lot of only some very advanced companies ...