Today Facebook begins rolling out file sharing to all Groups, and while it's got many restrictions, it could be good enough to limit the long-term growth potential of cloud storage / file sharing services like Dropbox, iCloud, and Google Drive. Music and any copyright files aren't allowed and file size is capped at 25mb, as Mashable first reported. But this is just the first version, and you can be sure Facebook will keep hacking away at it.
Facebook Adds "Good Enough" File Sharing To All Groups. Dropbox Should Worry About Growth