Check that the person waiving the copyright actually owns it. As for ideas you find there, they will clearly not be confidential as they have been placed in the public domain. Check if there are any notices limiting future use - as they could be legally enforceable. Also watch the problem over foreign laws. Virgin Atlantic was recently caught under US trade descriptions law because it did not update its Web page giving details of flights.
Singletons are specialist intellectual property solicitors.
If you have a legal question which you would like answered then please write to the Editor, Inventors World, clearly marking your envelope 'Inventors' Legal Problems'. We regret that, due to the complex nature of Intellectual Property Law, we cannot enter into personal correspondence, nor name correspondents.