Founded in 1997, BookFinder.com has become a leading book price comparison site:
Find and compare hundreds of millions of new books, used books, rare books and out of print books from over 100,000 booksellers and 60+ websites worldwide.
When is a Pig a Hog?:
The author of Webster's New World Guide to Current Usage skillfully explains the differences between related words such as pay phones and public phones, street and avenue, and couch and sofa. [via]