[jinnko]

Once upon a time, prior to Microsoft or eBay purchasing it, this is what Skype was. It required a set of central instances to be supernodes to facilitate discovery, then each client communicated with others directly. And IIRC any client up long enough and with sufficient compute and bandwidth, could become a supernode.

[Telemakhos]

Skype and iChat both did direct client-to-client communication. Skype was bought by MS, and Apple got sued by a CIA front company over iChat. The result was the same both ways: all comms started getting routed through a central server that could log metadata.

[bboygravity]

It also had the side effect of having far better latency than any modern day popular video calling app can offer.

[LunaSea]

It also had the side effect of making it possibly for any of your contacts to DDoA you because they had accès to your IPv4 address through Skype.

[yencabulator]

Historically, source IP was a lot more readily available. Every IRC user's source IP was visible, every UNIX login session's source IP was visible, and lots of people hosted their own websites which meant they saw your IP address there too. The implications of it used to be more like having an email address from a specific university. Skype happened relatively early in the world of online privacy.

[fsflover]

I don't understand why obsolete technologies by MS are often upvoted on HN and become the first replies, while the corresponding working, decentralized technologies go to the bottom. Matrix exists and has a preliminary P2P version [0,1]. Other messengers were also mentioned in the comments here. Another example of such tendency is here: [2].

[0] https://arewep2pyet.com/

[1] https://news.ycombinator.com/item?id=23393935

[2] https://news.ycombinator.com/item?id=44898242#44898884