Here are a few old wives' tales that I have heard recently:
"I found the information on the Internet, so I have a right to copy it and use it on my own Web site."
"Everything on the Web is free."
"If I attribute where I found it, I can copy it and use it."
"I can use that information as long as I don't charge for it."
"The original records are public domain, so I can legally copy that information from a book, CD-ROM or Web site."
"The information was published by a non-profit organization, so I can legally republish it."
"The information was not labeled as copyright protected, so I can use it."
"You cannot copyright facts, and I am only publishing the facts."
"Well, everybody does it!"
One problem: all of the above reasons are wrong. If you republish information without permission, you may find yourself receiving an unpleasant letter from a law firm.
Under U.S. copyright laws, all content today is copyrighted unless otherwise specified. It makes no difference if the information comes from the New York Times' Web site, from a non-profit society's site, or from cousin Lew's personal Web site: you cannot copy and re-use that information without permission. It also makes absolutely no difference whether you charge money or not. Likewise, attributing the source makes no difference. Publishing someone else's material without permission is illegal.
For further details, you might want to refer to the following:
U.S. Copyright and Genealogy by Mike Goad: http://stellar-one.com/copyrightgenealogy/
Copyrights & Wrongs by Mark Howells: http://www.oz.net/~markhow/writing/copy.htm