Microsoft recently announced that OneDrive cloud storage account users would no longer have "unlimited" storage, and that free users would be reduced from 15GB storage to 5GB (which is similar to other "free" tier offerings from Dropbox and the like).
The "unlimited" storage was originally offered to Office 365 subscribers, who will now be limited to 1TB, after Microsoft cited abuse by some users.
They are now allowing free users to be able to "opt out" of the decrease from 15GB to 5GB, at least for the time being.
Microsoft's OneDrive was originally FolderShare, which was purchased by Microsoft and presented as Windows Live FolderShare. It has gone through several iterations in the last few years: LiveSync, Mesh, Windows Live Mesh, SkyDrive, now OneDrive.