Your data in the cloud is the data of the cloud service's.
Your data is protected. Your cloud service resident data is not.
My rule is simple. If I cannot point at the drives my 0's and 1's are ultimately stored on, and the drives I point at do not belong to me, operating in in computers I own, it isn't mine. I don't have a fleet of lawyers to navigate the "technically mine" ToS/EULA minefield.
If I own the hardware, and I own the software on it, it is mine. Otherwise, short of levels of audit I find extremely unpleasant, it's an arms length arrangement I personally am intensely uncomfortable with given the track record humanity has demonstrated with prioritizing short-term self-interest against not doing questionable things in the long term.
I find this simplistic treatment of things, while making my life and software choices fewer in number, and less polished, tends to keep my friends and family out of trouble and harms way. They know the lecture is coming, and they still come see me anyway.
What even is "data"? If you mean "my data is the way in which I interact with a website. It is personal to me and is my property.", then surely you must also say "my mannerisms when I talk to you are personal to me, and you may not remember them without my consent".
The Quantum Thief series takes this to its extreme, with a technology called "gevulot" which does exactly that by way of a societal exomemory. You can choose to "reveal" any aspect of your self all the way up to your appearance on a person-by-person basis. Highly recommend the book!
The legal system of the U.S. recognizes Third Party Doctrine.
I am not an espouser of that legal philosophy. I draw a hard line. Business with me is no one one else's business but me and the customer in question. I believe there is an expectation of privacy in business affairs.
I call it Professional Discretion.
Yes, before you ask, this makes my life comparatively miserable in today's world. No, I'm not amenable to changing my view on it, because I've seen enough of how the rest of the world treats it to realize just how pathological things become when no one respects anyone else's privacy anymore.
You can ask. But it's up to me to say yes. Everyone else has trouble even grokking the concept of asking anymore.
The only person you can control the affairs and effects of is you.
Big data beat the trust out of me. The bigger the dataset, the more likely it is to attract abuse. I started out my computing career with what others described as a near martyr level of dedication to keeping my customers data private. I'm still that, but after working for everyone else in the industry and finding that the moment you give them a scrap of data, you just kicked off a chain of 3 or 4 bulk transfers to people you aren't even aware of...
I can't control them. I can only echo for people the importance of understanding:
no one is nice until proven otherwise. Not even me. Trust only what you have made, or what you yourself have been gifted, and can modify.
It is shared data. You can use it for whatever you like, so can who-ever controls the other location it is stored at (unless encrypted and only you hold the keys).
whose data is it anyways?