Another great TBL piece on popular misconceptions about links:
The ability to refer to a document (or a person or any thing else) is in general a fundamental right of free speech to the same extent that speech is free. Making the reference with a hypertext link is more efficient but changes nothing else…
Users and information providers and lawyers have to share this convention. If they do not, people will be frightened to make links for fear of legal implications. I received a mail message asking for "permission" to link to our site. I refused as I insisted that permission was not needed.
There is no reason to have to ask before making a link to another site
(Thanks, Patrick!)