Cyndi's List and other lists of web links are one way of approaching this question. But there is another useful web site that can be used to find various kinds of information. This site is called WorldCat.
So, what is WorldCat? Why is it important?
WorldCat is a product of a company called OCLC. Originally, back when it was founded in the 1960s, it stood for Ohio College Library Center. These days it stands for Online Computer Library Center. WorldCat is a union catalog, (a combined online library catalog describing the collections of a number of libraries), which at this writing itemizes the collections of 71,000 libraries in 112 countries. The key thing here is that the libraries must participate in the OCLC global cooperative. WorldCat (hereinafter WC for short) is built and maintained collectively by the participating libraries.
At the time of writing the LDS Family History Library) is not a member of OCLC. So, anything that is in the Salt Lake genealogy library, Granite Mountain, or in any of the branch Family History Centers (FHC), does not show up in WC. The FHC where I volunteer has several hundred useful genealogy books, including cemetery records, but you just have to know that those materials are located there.
WC was created in 1971, and it contains more than 150 million different records pointing to over 1.4 billion physical and digital assets in more than 470 languages. It is the world's largest bibliographic database. OCLC makes WorldCat itself available free to libraries, but the catalog is the foundation for other fee-based OCLC services (such as resource sharing and collection management).
The key point to remember is that WC gives you information about information, and not information itself. That is, you get titles, authors, subjects and locations like a regular library catalog. What you do not get is actual data or books such as that provided by Ancestry.com. Heritage Quest, Familysearch, etc. Nor do you get what you might get from Google Books, which is digitized pages of actual items.
For example, my library has done almost 2 million pages of digitized documents of all types, and over a million names in various databases. But because only some of these are described in the catalog, only those that have been cataloged will show up in WC.
Our Life Records search page has almost 1 million references to births, marriages, and deaths in the Rochester papers over the last 55 years. You can search it for free. But the data itself is searched online, and it's available off a web search page. It has not been cataloged and so doesn't show up in WC.
And the very useful web site with over 11 million pages of OCR's upstate New York papers, www.fultonhistory.com, also does not appear in WC. Nor do the papers at the Northern New York Historical Newspapers, which is another free newspaper search site.
In 2003, OCLC began the "Open WorldCat" pilot program, making abbreviated records from a subset of WorldCat available to partner Web sites and booksellers, to increase the accessibility of its member libraries' collections. In 2006, it became possible to search WorldCat directly at its website. In 2007, WC began providing pages for 20 million 'identities', predominantly authors and persons who are the subjects of published titles
What actually is WC? I can quote from some of their publicity materials:
WorldCat is a cooperatively-created catalog of materials held in more than 7,600 libraries in the United States and the rest of the world, including public, academic, state and national libraries; archives; and historical societies. These libraries have cataloged their regular collections as well as many special collections—including digitized materials—devoted to local history. This makes WorldCat a unique tool for your research into your heritage.
Because WorldCat is a "super" catalog of more than 1 billion library holdings representing 54 million items held in libraries, you can reduce the number of places you search to locate useful material. WorldCat complements tools such as the LDS Family History Library, Ancestry.com and ProQuest's HeritageQuest –- but it does NOT replace them
So, how is this useful for genealogy?
So is this worthwhile for genealogists? Or would their time be better spent elsewhere? My opinion is that it is worthwhile for finding clues in your research. You can serendipitously come upon items that you might not have thought of, or libraries that you did not know about which have very useful collections. It's another useful tool in your research.
Some examples of the types of materials you can find citations for in WorldCat are listed next. But remember, they are neither the actual items nor a digitized version of them. They are guides to where you can find these materials.
Historic newspapers (some of which have been cataloged and preserved through the United States Newspaper Program, including newspapers in many languages); Newspapers from non-U.S. countries; Historic photographs (e.g., from the collections of the Denver Public Library Western History/Genealogy Department and the Colorado Historical Society); Church histories; Cemetery records; Civil war and other military records; Town histories; Slavery and anti-slavery materials; Black biographical dictionaries; Oral histories; Diaries and journals; Probate records; Burial records; Obituaries; Microfilmed genealogy and local history collections; Indexes to wills; Indexes to births, marriages and deaths; Family histories; Family bibles; Manuscripts from archives; and general genealogical resources such as directories, handbooks and magazines
As an example, WC does return items that have been digitized and gives you the link to then load them. There is a title called, The Civil War diary of Captain N.S. Baker, which is a nice little book about that conflict. The original is in grievous shape, so it has been digitized. There are records to be found in WC for both the print and the digitized version. As always, the holding institution must have put it in their catalog database for it to be found. The WC record does not indicate when the item in the records has been digitized, but that is usually found in the record in the catalog that you click to from WC.
This particular title does not give a clickable live link to the Rochester record, but it does drop you into our catalog and the search can be run from that page. In this case it is also cataloged as part of a monographic series, so clicking on that in WC does show all the titles in that series in WC. So, WC only points to the place holding such digitized records (providing those records have been cataloged). To further illustrate, WC has for this title = Format: application/pdf. Requires Adobe Acrobat Reader. Format extent: 12.0 MB. Document has optical character recognition capabilities. Digitized version of print original. Description of original:  leaves; 28 cm. Original is a typewritten copy of a diary and three letters dated 1862 to 1864. Material copied by A. Porter S. Sweet, author's grandson. Description: 101 p A fuller record with a clickable link is found in the (local) catalog when the item is searched there.
What WC it is not.
Well, it's not the actual data that is presented. It's not the census itself, but it tells you where guides to census are, and cataloged holdings; it does not have descriptions of photographs unless thy have been cataloged. While Denver is mentioned above, the 22,000 photos that are "cataloged" and fully described individually in our library's Rochester Images database do not appear because of the main library catalog software's inability to include them. WC would include compiled indexes to births, marriages, and deaths, but not the 5500 microfiche New York State vital records index from 1881-1959, because by law it cannot be put online or cataloged. We have it, and describe it on a web page. But it cannot appear in a union catalog such as WC.
Access to this database.
You can get access to WC, generally, through libraries which make it available as a choice in their in-house database choices. But you can also search it at www.worldcat.org, from home for free. In 2006, it became possible to search WorldCat directly at its website just mentioned. In 2007, WorldCat Identities began providing pages for 20 million 'identities', predominantly authors and persons who are the subjects of published titles.
And there is an app for that! If you have an iPhone, you can purchase the WC iPhone app for 1.99, at the time of writing
Following are the answers to common questions, taken from the WorldCat website FAQ.
- Is WorldCat free, or can I subscribe to it if my library doesn't provide access?
WorldCat is available exclusively through libraries or other organizations, and is not available for direct purchase by individuals. However, many libraries have access to it, and several states have purchased a WorldCat subscription for all of their residents. If you don't see it listed on your library's Web site, ask for it. The library may not yet have provided a link to WorldCat. [Author's note: But it is free to search from home, as noted above.]
- Now that I have access to WorldCat, how do I find what I need in it?
Finding materials in WorldCat is similar to finding materials in your local library catalog. Often, researchers can find pointers to useful material by simply searching for a family name or a specific location, alone or in combination with genealogy terms.
- I've found something in another library that looks useful—how do I get it?
There are several things you can try:
- Ask your librarian if the library will borrow it for you—and whether the holding library will lend it—or ask if the holding library is willing to make a photocopy or scan of applicable portions of the material for you [Author's note: We do not lend our our microfilmed newspapers, but the state library does. Ask your local librarian].
- Try looking for the material at Web-based booksellers, now that you know it exists
- Drive to the holding library, if it's close enough—it might just be worth it to examine the material in person; or Locate a researcher in the area who would be willing to visit the holding library for you; your librarian may be able to help you do this.
So, how can you learn to use this?
You can search the terms WorldCat and Genealogy in Google, and you should find a slide show put out by the state of Nebraska on Slideshare.
Or try Googling: worldcat genealogy tutorial - for more links to online ways of reading about and seeing it.
And WC includes OAIster – which is yet another union catalog of millions of records representing open archive resources that was built by harvesting from open archive collections worldwide using the Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH). That has more than 23 million records representing digital resources from more than 1,100 contributors.
As another example, I searched my own name, as some of my scribbling has actually been published. What I found in WC, was the following kind of information regarding this. I found entries which give the titles of the works; the author, the publisher, place and data if known, the format and language that the item appears in. It then offers to connect you to that online catalog so that you can search and find out more data and the circulation status of the item. You can also put in a zip code to see which libraries are closest to you, and even limit the result to libraries holding only the edition that you are interested in researching.
Remember, this started out as a tool for collaborative cataloging more than 40 years ago, and not as a for-profit genealogy search site. In fact, it even gives you the distance to the nearest holding library!
It will connect you to OCLC FirstSearch, which is another service that helps to tell you where the found items can be located and used.
The entry gives you the title, the author's name, the OCLC number (used for inter-library loan), notes such as when updated, a physical description of the item (wouldn't you love to know if it's 500 or 100 pages, or only 2 typed onionskin sheets?), and who published it.
As far as the entries for my name go, it showed 16 works in 18 publications, in 1 language, and that 71 libraries hold copies of them. It also offers to search for publications by or about a topic -– useful for locations and more well known sorts of people. It had the mostly widely held titles I have done, when published, what language, and how many libraries hold them.
Another nifty thing is that the catalog is not restricted to just books. It can also include audio visual materials. Some years ago I made a video (sigh - I thought I had bought up and burned all the copies, as I am not handsome), which talks about the library where I work and what research materials we had at that time. (Another caveat – things are fixed in time when they are recorded. We have many more things available now than when I made the video). It also has sound recordings, such as tapes of lectures on various topics. If someone mentions your name of interest, that name appears. I was used as a source for a Civil War book by another author, and because of that I tag along on his record, and it appears when you search my name. Still more -- WC gives related identities, which can mean co-authors or subjects. Speaking of subjects, it gives clickable and searchable links to whatever subject headings have been assigned to your works of interest. I was really surprised to see all that it offered.
Difference from Google Books
Google Books is a service from Google that searches the full text of books that Google scans, converts to text using OCR (optical character recognition), and stores in its digital database. When I tried Google books, it reminded me of some things that I had contributed to years ago and forgotten about! But what I got, for the most part, were snippet views, just the small part with my name. [another note -- sometimes you do get full text items]. It gave a series of choices as to where to buy the title using the clickable links to Abebooks, Alibris, Amazon, Google Product search, and finally, "find in a library."
The difference is that WC helps you to do subject searches and make logical intellectual links.
For those reading who are interested in getting academic credit for providing such services, I did find a link for that purpose at the University of Wisconsin, School of Library & Information Studies.