Condos differ from time shares. In a condominium, you own 100% of a unit and everything inside the boundaries of that unit is your responsibility (repairs, damage, upgrades, etc). You also have exclusive access to that unit (nobody else can use it, unlike a time-share).
You own a fraction of the land that the building sits on, and a fraction of the "common areas" (lobby, swimming pool, parking lot, etc). You are responsible for contributing for the maintenance of those areas, or paying assessment fees to a management company that will take care of those areas.
Why would that be a scam? If anything, it protects the unit owners from things like the landlord selling the building and forcing everyone to move. You can't sell an entire condo building and land without clear title from every single unit owner.
