Decentralized backup?

Question

Backup

For a long time on Habré I saw an article about a program (not BitTorrentSync) that, through P2P, allows you to provide free space on your hard drive for the needs of storing other users' data and the ability to use the free space of other participants to store their files.
I don't remember any names and I can't find it anywhere.
As far as I remember the program was free

Answer 1

Once upon a time, Wuala provided such an opportunity, but it was canceled a long time ago , and now even free accounts are being closed .