For a long time Skype's P2P architecture worked great. It was the absolute best A/V calling experience, handily beating every other contemporary mainstream offer from MSN to Y!IM. It had issues such as getting crushed by patch Tuesday, and I assume it was likely not robust enough to adversaries, but one thing you can't say about Skype was that its P2P architecture didn't work. It absolutely did.

I think even though there were many things that could've lead to the demise of Skype's P2P network, it was pretty undoubtedly the rise of mobile phones. Android or iOS, Skype was just dreadful; they were clearly ducktaping mobile support in. Sometimes you'd be sending messages and everything would appear to be working, little did you know the other person was responding but you weren't actually seeing anything. Push notifications? Sometimes you get them, but it was a crapshoot as to when you would get them. It probably was expensive to try to bridge their P2P network to mobile phones, and it definitely didn't work very well.

I guess anyone can just say these things and it's really difficult to back them up since a large part of it is subjective (and aside from some reverse engineering efforts, I am not really intimately familiar with much of the details behind Skype and its transition off of P2P) but I think there is one thing that most people would definitely not disagree with: Skype was far more relevant and well-regarded when it was peer to peer. That's not to say that the move off had anything to do with its downfall, more just to say that if it was so awful, I think it would've been the other way around.

> it worked so badly.

Skype has a much worse quality now after the switch for all people I know who used Skype at the time.

The real reason for switching was iPhone. First, Apple did not allow long-running apps in favour of centralized notifications. Periodically start Skype to check events did not help recwicing calls. Second, users moved to smartphones, which depleted the active nodes network. So there has been an increase of short-lived nodes without balanced increase in long-lived. So to prevent the p2p network model to start failing, Skype moved to a centralized one. And probably the government regulations (to store and decrypt messages) took place, but this was probably not very public.

Microsoft buying Skype must have added additional incentives to centralize. Regulatory, organizational control, auditing, etc. And tinfoil take would include surveiling.

Skype was P2P pre-acquisition.

Microsoft’s acquisition changed Skype to centralize it through their servers (and introduce all sorts of call quality issues).

It’s less about focusing on tinfoil and more about how creating $ for cloud usage, which allowed for centralization and surveillance.

Skype has been enough of a turn off from the performance issues it has / had hat many people moved elsewhere.

In the early 2000s there was a lot of discussion about a US law that required phone providers to provide for wiretapping, with no mention of the underlying tech. Being P2P, that wouldn't work for Skype, so a journalist asked the Skype CEO whether they would comply with the law and he said "We're not US company. Why would we?"

So I don't think it's all that tinfoily to think that once Skype became a US company, the government might have pressured them into making wiretaps possible, since there was a specific law that arguably required it. Considering all that Snowden revealed later, I'm not sure I'd put any digital surveillance in the tinfoil category.

Microsoft at that time said they are moving Skype to centralized server from distributed to reduce code complexity.