> I can believe them [WhatsApp] when they say they don't keep data.
If that's true, I'm in awe of their integrity. Skype on the other hand now has complete disregard for user privacy. Skype stores your voice mails and video messages forever[1]. This is something that they started doing 2-3 years ago and few people seem to be aware of it. It's amazing how low Skype fallen from its early days when it was considered a beacon of privacy and on the cutting edge of encryption and security.
[1] Details: Clicking on Preferences -> Privacy -> Delete history (OS X) or Options -> Privacy Settings -> Clear history (Windows) pretends to delete the voice/video messages but it merely hides them from your view. If you re-install Skype on the same computer or run Skype on a different computer, all those "deleted" voice mails and video messages re-appear. The delete and clear buttons are basically lies; there's no polite way to put it.
Skype was never a reliable option. They never published their protocols or security (just that one "review" iirc). They took many measures to prevent people from inspecting the client.
I thought Skype only stores the last 30 days of data on their servers, while it will store every piece of data received on your local computer indefinitely (unless you delete it, of course).
No. I personally have a video message that is almost 3 years old that I've tried to delete multiple times over the years and it still shows up if I do a fresh install of Skype on a new computer.
Very old voice messages are also accessible even if "deleted".
Text chats do seem to disappear, but at this point I don't believe anything Skype says. I figure they keep the chats forever as well.
Chats are definitely saved, but files aren't. You can't retrieve files after certain amount of time. I can also retrieve conversation from 3+ years ago. I don't remember if there is an option to forget conversation history though.
storing data for 1 billion users and maintaining consistency is a pain the butt operationally. Whatsapp isn't storing the data. If they are, they're spending hundreds of millions on servers for data they can't monetize easily without alienating all of its users.
If that's true, I'm in awe of their integrity. Skype on the other hand now has complete disregard for user privacy. Skype stores your voice mails and video messages forever[1]. This is something that they started doing 2-3 years ago and few people seem to be aware of it. It's amazing how low Skype fallen from its early days when it was considered a beacon of privacy and on the cutting edge of encryption and security.
[1] Details: Clicking on Preferences -> Privacy -> Delete history (OS X) or Options -> Privacy Settings -> Clear history (Windows) pretends to delete the voice/video messages but it merely hides them from your view. If you re-install Skype on the same computer or run Skype on a different computer, all those "deleted" voice mails and video messages re-appear. The delete and clear buttons are basically lies; there's no polite way to put it.