I'm wondering if others who use the Skype desktop app on the Mac have noticed it downloading ridiculous amounts of data and/or have any idea what it's downloading.

I use Skype exclusively for chat with a particular contractor. No calling, no video, just text chat with a handful of images and an occasional link. I've been on a very slow internet connection (~0.25% of what I'm used to) while traveling, so have been sensitive to things doing a bunch of network transfer in the background that I normally just don't notice.

I've discovered that Skype, of all things, seems to be the worst culprit by far. After a few days of monitoring, it had racked up well over 2GB of network download, with nothing but the single chat sitting open in the background. It's not constantly downloading; it'll sit there quietly for long periods then suddenly max out the internet connection until it's downloaded hundreds of MB of... I have no idea what. It is completely baffling to me how it manages to do this or why.

The best guess I've got is that it periodically decides to sync the entire years-long chat history, or maybe to refresh all of the web previews. Oddly, there doesn't seem to be any settings to limit the amount of message history stored without just deleting the entire chat, which is kind of ridiculous as well.

I suppose it's possible the iOS version does this as well, it's just not as easy to see network activity on iOS.