It's not about your space, it's about your payment. If someone like a pro photographer shares their stuff with clients all the time, then their dropbox subscription won't necessarily cover all of that bandwidth. [1] Companies like dropbox only mention bandwidth in fine print or buried somewhere deep in the FAQ, but bandwidth is a key resource that every dropbox user consumes and dropbox has to pay for.
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[1] It might if dropbox was a more lean operation, but it isn't.
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[1] It might if dropbox was a more lean operation, but it isn't.