This is pretty nifty. Though sadly many of these constitute "you can send a letter asking them for it", which is somewhat painful. That being said, it would be intriguing to see what response I got back in a few cases, especially since I'm in the US, and they aren't really obligated to respond.
OTOH (e)mail has the advantage that it lands as a written record in your inbox and you are in control of it, not kept behind a service which might disappear overnight.
I don't think these are all correct. But i'm not sure if this page will change after the GDPR comes into effect.
I'm just taking the Facebook one as an example; it links me to the official download page on Facebook itself. I downloaded this, but it didn't contain a whole lot of data. In fact, it contained nothing about the data it collects using its 'tracking cookie' / like buttons. I absolutely 100% expect them to have a database somewhere of the pages i've visited that have either a like button, or a tracking cookie.
Then again, maybe i'd just need to send them a data request after the GDPR comes into effect to be sure.
