At least part of the idea behind Freecycling is to have some discretion over who gets your good stuff that you don't need -- the foster family suddenly blesed with infant twins, for example, and not the dealer in second-hand goods. Also, many items that move on to new homes through Freecycle would not survive a night at the curb without damage -- a television set, for example, or books or china.
The City of Ottawa doesn't like the free-at-curb approach either. I think the notion of citizens strolling the boulevards to pick over their neighbours' cast-offs rather offends something deeply suburban and socially ambitious in the average bylaw enforcement officer. They'd rather see the same activity carried out on Saturday mornings under the guise of the garage sale.