IANAL, but...
To reuse copyrighted content, you have to consider fair use eligibility and such -- but fortunately, not all data is locked down by copyright.
One of my favorite ten USSC rulings:
http://en.wikipedia.org/wiki/Feist_Publications_v._Rural_Tel...
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It is a long-standing principle of United States copyright law that "information" is not copyrightable, O'Connor notes, but "collections" of information can be. Rural claimed a collection copyright in its directory. The court clarified that the intent of copyright law was not, as claimed by Rural and some lower courts, to reward the efforts of persons collecting information, but rather "to promote the Progress of Science and useful Arts" (U.S. Const. 1.8.8), that is, to encourage creative expression.
Since facts are purely copied from the world around us, O'Connor concludes, "the sine qua non of copyright is originality". However, the standard for creativity is extremely low. It need not be novel, rather it only needs to possess a "spark" or "minimal degree" of creativity to be protected by copyright.
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In the late 1990s, Congress attempted to pass laws which would protect collections of data, but these measures failed. By contrast, the European Union has a sui generis (specific to that type of work) intellectual property protection for collections of data."""