From the OCLC website:
WorldCat.org lets you search the collections of libraries in your community and thousands more around the world at once then locate it in a library nearest to you. You can search for popular books, music CDs and videos—all of the physical items you're used to getting from libraries. You can also discover many new kinds of digital content, such as downloadable audiobooks. You may also find article citations with links to their full text; authoritative research materials, such as documents and photos of local or historic significance; and digital versions of rare items that aren't available to the public.
WorldCat lists let you keep track of items (books, videos, DVDs) of interest that you've found on WorldCat and refer back to them whenever you want to. You can share your lists with friends and colleagues, too.
Here are some ideas for lists you might want to build: movies I want to check out, books I recommend, preliminary sources to review, cited sources, books to read to my child, Living room decorating ideas
Here are two lists for example that we created:worldcat oclc