A hammock-canoe drawing, U.S. Patent No. 299,951, is displayed in a June 1884 publication of the U.S. Patent and Trademark Office in Alexandria, Va. Critics of the patent system say it's too easy for people to save a slew of semi-realistic ideas, then sue when a firm separately tries to make something similar. Bloomberg via Getty Images hide caption

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Some colleges and police departments are starting to use software that scans social media to identify local threats, but most tips still come from members of the public. Ikon Images/Getty Images hide caption

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Awash In Social Media, Cops Still Need The Public To Detect Threats

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