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The Web is full of short URLs such as bit.ly/cwd2hp. The products of URL-shortening services--bit.ly, Tiny URL, and others--these cryptic URLs appear on social networking sites such as Twitter--and increasingly in other places on the Web as well. Those shortened links are useful for people posting them, but they pose a problem for the people who might want to follow them. Before you click, you have no idea where they lead.