Unless you have the author's written permission, you are guilty of copyright infringement. Broderbund, one of the largest producers of genealogical CDs, clearly spells out what copyright violation of its CDs are, yet users continually infringe. You can not copyright facts, ideas, concepts, principles, discoveries, titles, names, slogans, short phrases, blank forms, general topics, common plots, or themes. However, by adding any kind of narration to the basic genealogical facts gives rise to a copyright in the creative portion of the work. If you submit your data to any of the popular computerized family trees, you are implicitly agreeing to allow your information to be published.
Web pages are creative works and thus are copyrightable.
A favorite site of Web thieves is Cyndi's List with its more than 30,000 links to genealogical sites. They are under copyright also. However, many graphics artists will provide you with GIFs or JPEGs, but please read their conditions first, and follow them. Because of cyber thieves. I am more than willing to share my genealogy, including sources, with my cousins, but I want to be asked first.