And while I'm revisiting the subject, I'll mention that unless I've missed something, a major advantage that ImageShackUploader offers over Dropbox is an immediate set of links on my desktop when I upload an image, whereas as far as I can tell, I've got to visit dropbox.com to link to images uploaded there.
You've missed something: the contextual-menu will give us a link right in Finder. I never visit dropbox.com for anything (anymore).
With regards to the cookie situation, thanks for the great sleuthing. As mentioned however, visiting dropbox.com
directly is virtually unnecessary.