I have an email notification from Dropbox in December of last year saying this will be disabled.
They probably should have had some warning on the app itself when putting or sharing files from that folder.
It's a free service, so my bad for using it without a good backup, but I had used programs for a long long time that produce screenshots with one keystroke and copy the URL to the clipboard, saving time.
I figured this was relatively low overhead for them and a popular feature, so they would keep it. Lesson learned ..
Disclaimer: I've been fed delicious lamb chops and duck at the DB office, so my view might be tainted.
Edit: I also received another email about it on March 1st
Looking over the past 6 months, I don't have anything else but "Hey, you added a new device to Dropbox!"