Actually I’m surprised this took so long to do, and in the light of doing so shows that perhaps Twitter was sold for its existing content rather than existing or active user base.
Not a very significant distinction: if active users stopped posting, scrappers wouldn't have much of a reason to keep scrapping.
Age may be included as part of the training but they generally want to suck up as much data as possible.
It's shared ownership. You own it, but give Twitter non-exclusive permission to also use it.
This is why news agencies request permission from a twitter account before sharing a picture they took.
It may seem weird weird to compare useful content to a used napkin, but hey, successful business founder stereotypes do quite often involve have an idea written on a napkin…
Yes, it’s a mistake to rely on social media content remaining up forever, agreed. That’s separate from ownership. Backups are important even for data on a hard drive you physically own, since hard drives can fail or be damaged or lost.
I can own a picture, but I can't place it on the NY Times website.