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I just found out DropBox(free) and I'm not sure if using it as a private storage for file uploads for a website is allowed and is not considered an abuse of their service.
For example, a blogger displays in image in his/her article and that image is stored in his/her dropbox.
Or a portfolio site of an artist featuring his/her artwork samples in his website and those pictures of his art are stored from his/her dropbox.
And how about a small commercial website like a website of a restaurant featuring its dishes?