Project Gutenberg (often abbreviated as PG) is a volunteer effort to digitize, archive, and distribute cultural works. Founded in 1971, it is the oldest digital library. Most of the items in its collection are the full texts of public domain books. The project tries to make these as free as possible, in long-lasting, open formats that can be used on almost any computer. Unlike some other digital library projects, Project Gutenberg does not claim new copyright on titles it publishes. Instead, it encourages their free reproduction and distribution. As of December, 2006, Project Gutenberg claimed over 20,000 items in its collection, with an average of over fifty new * e-books being added each week.