SocialFolders recently changed their business model and launched a paid account.
The free accounts were restricted to 3 services and 500 files. Paid account had access to unlimited number of services and 5000 files.
The company has reevaluated these plans based on user feedback and the new limits are more generous.
Free accounts would now be able to manage 2000 files. Paying subscribers get to manage unlimited number of files. There is also an invite system in place. For every successful invite, both users get 1000 extra files in their accounts.