When I first heard about Jeffrey Paul's claim [NSFW] that OS X 10.10 Yosemite was leaking data to Apple's servers, my first reaction was "yeah, yeah - that's the way autosave is supposed to work."
But I was wrong.
Yes, some people that have upgraded to Yosemite directly from Snow Leopard are being caught out by the way autosave works, something that the rest of us have got used to.
The idea that users shouldn't have to worry about whether they've saved a document or not is exploited by Handoff, the Yosemite Continuity feature that lets you move almost seamlessly between working on a iCloud Drive document on a Mac or an iOS device.
That wasn't what Paul was talking about.
What he discovered is that Yosemite sends the current document state to iCloud Drive.
From Lion to Mavericks, 'unsaved' data remained on the Mac's local file system (in a folder called Saved Application State, which was located in the user's hidden Library folder).
According to Paul, Yosemite's blabbing applies to all applications that save their state. Furthermore, the list of recently used email addresses is also sent "silently" to Apple.
As he pointed out, this can be "useful" (e.g., in conjunction with Handoff) but it means "Any open and yet-unsaved document within an app is now silently and automatically uploaded to iCloud Drive, and, by extension, the government."
According to a traffic log collected by Landon Fuller, the contents of the files are actually sent to Amazon's S3 storage service.
Fuller previously pointed out that "In Yosemite, all Safari web searches are sent to not only the search engine you've selected (e.g., Google, DuckDuckGo), but *also* to Apple, even if you've disabled 'Spotlight Suggestions'."
He has also drawn attention to the fact that while Apple uses anonymous session IDs for Spotlight queries sent to the web, "the query URLs are server-supplied, [so] they can be modified to include a permanent identifier without triggering any visible client behaviour."
At a certain level, you have to trust the organisations that provide your software or you simply wouldn't use it.
(I'd remind open source fans of the the Heartbleed debacle where a serious vulnerability went undiscovered for years, and in any case very few of us have the time or expertise to examine source code or network traffic logs.)
But when companies like Apple make questionable decisions, it makes it harder to trust them next time.
Would it have been that much less convenient if Apple had continued to store application state locally, at least until the user made the decision to save the document in iCloud Drive?
There's always a tradeoff between convenience and security or privacy, but aren't users entitled to think that their data is stored locally until such time as they explicitly save or copy it to a cloud server? I believe they are.