Watching some of the highlights of Marc Zuckerberg’s testimony before Congress, I see lots of Senators asking him yes or no questions such as, “do you believe FaceBook users have a right to download or delete their data.” Zuckerberg’s response was an unequivocal “yes, Senator” in all cases. But when asked questions about allowing users to decide how data accrued on them could be used or corrected, Zuck began to backpedal and attempt to slip back into tech speak.

It’s really important to understand why he pulls short when asked about deleting or correcting erroneous data. One reason is that all the questions asked to that point were about the “user’s data,” which Zuck can very quickly and easily answer in ways that make the Senators happy.

Because those answers were already beaten out of FaceBook a decade ago. Then, the question was about copyright: FaceBook originally claimed copyright ownership over your photos and posts, a notion which was received with howls of condemnation at the time. The result was a change in FaceBook policy which carved out for itself a limited license for that kind of data.

All of which is to say no: FaceBook does not own your “data,” nor does it hold unlimited copyright to it. Yes, you already have a legal right to all of that information, including your posts, comments, likes, photos, uploads and the whole kit-and-caboodle.

But companies like Cambridge Analytica (and Coca-Cola. and Pepsi. and Sony) are really after is the metadata that is created by the pattern your data creates. The fact that you “like” Roseanne is a lot less important than the fact that you watch more FaceBook videos at 3pm than other times of day. You are available to be advertised too and influenced at those times.

Holding on to actual data about any one individual is a waste of server space, even if you think you might want an archive for some reason. What matters is the ability to observe behavior in real time. That’s why “meme” images with sloganesque sayings on them are so important: you can send one out that’s intended to seem racist and watch what happens.

How long does the average person look at that image? The average Republican? The average 4-year degree holder? The average cop? Does the length of time they look at an image correlate to likes and comments? Does it even need to?

None of this data is “yours.” It wouldn’t exist in digital form without FaceBook providing a platform and third-party businesses aggregating it into actionable insights. Which is why “correcting” data about you is so important and so difficult for Zuck to agree to: that would require that companies open up their data operations to allow you to see their assumptions of you.

Doing so would most likely be an infuriating experience for the end user and a nightmare for businesses. Which isn’t to say that they shouldn’t allow us to see what their assumptions are. But that’s what I think the line he’s going to try to skirt will be.