Whist not wishing to put you, or myself, at any risk of litigation, I think that it is fair to assume that:
- All content on the web is copyright, whether or not there is any message to that effect.
- You require the permission of the copyright owner to embed their content in your site.
- Do not assume that the owner of a site owns the copyright of all the material on their site.
- If you are in any doubt, seek legal advice from a qualified legal practitioner.
Keep that in mind and,hopefully, you should not go far wrong.