[The Saucepan Man]

Originally Posted by The Might

I was wondering about quotes.
How big does an excerpt have to be to be considered illegal, and no longer a legal quote?

Any quotation from a literary work beyond a mere name, title, slogan or phrase will generally constitute a breach of copyright in that work. However, under the "fair dealing" exception, it is permissible to make single copies or take short extracts of works when used for non-commercial research or private study (although sufficient acknowledgement of the author should be included).

Originally Posted by Menel

I, however, am from the U.S., where things are probably different.

The US Copyright Office website looks to be a useful resource in this regard. From a brief review, US law in this area looks to be broadly the same in terms of the points addressed above.