[FrojoS]

Is this smart? What if hundreds of millions of people now start doing hour long calls during this month? If the quality goes down, this wouldn't be good advertisement and would also anger existing costumers.

Is VoIP bandwidth so low by todays standards, that they can scale without problems if they have to?

[r3m6]

Skype is peer to peer. That this THE clever invention that put them ahead of all competing services when they launched. They can scale without any significant additional bandwidth or server costs.

[macuenca]

This is true only for Skype to Skype connections. Calls that have to reach The PSTN[1] need to be routed through telephony servers somehow, exposing the possibility to cause some stress on Skype's servers as FrojoS mentions.

[1] http://en.wikipedia.org/wiki/Public_switched_telephone_netwo...

[sp332]

Most of the data may be peer-to-peer, but the infrastructure is more centralized since Microsoft bought them. http://arstechnica.com/business/news/2012/05/skype-replaces-...

[trotsky]

yeah, its so low. im not sure what skype uses for a codec on pstn interconnects but it's probably better than most given that its easy to upgrade a closed ecosystem. Speex vbr at 16 is probably pretty middle of the road for voip, it doesn't sound that great but people put up with worse. leaving room for overhead and jitter still puts you over 5000 concurrent 16kbit channels, and id be surprised if they saw more than a few percent of their outbound customers active at any given time. standards based equipment is super cheap too as the protocols and such were designed to be managed by embedded systems.