Quoting on a blog, is it legitimate?

In our Internet Marketing Clinics, the question has arisen about whether it is legal to post information from another web site on your blog. I recently posted a quote from the Smithsonian Magazine to a blog I maintain, and sent them an e-mail notifying them that I had done so, and asking for their approval. I received the following note:

"This is in response to your e-mail informing us that you have linked an article on your website to the abstract of the article, "Can Great Coffee Save the Jungle?" by Katherine Ellison (SMITHSONIAN, June 2004, pp. 100-107) on our website, www.smithsonianmag.com. You ask whether this form of use is acceptable to us.
Your use does fall within our permission guidelines, in that you have quoted a very small part of the text (less than 200 words) and linked to our website (rather than posting the article on yours). However, as a courtesy, you may also wish to contact the author (who holds the copyright to the article) to inform her, and you might include her name in the text on your website."

I think this serves as a good guideline for quoting from other sources. Note that this refers to the policy at a particular magazine,and others may not have the same policy. The principle involved is that you should quote only a limited amount of text, and you should cite the source and link to it. Few sites are likely to object if you follow these simple guidelines.