For the past week or so, the Family History Archives has omitted their running count of total items in the collection. It has now appeared again with a jump of over 1700 new digitized texts. As of 14 July 2009 the number stands at 38,452.
I am personally aware that at the Mesa Regional Family History Center there is an ongoing scanning project that is contributing books to the online collection. In examining items on the shelves, I know there are a lot of books and other compilations at the Mesa Regional Family History Center that are entirely unique and likely not available at any other location.
The benefit of the scanning project is that many old and out of print or very limited edition items are being reproduced and made available to anyone with Internet access. Unlike other more general collections of digitized materials, these books are all genealogy and family history related items.
The books suffer the same or similar limitations of all early family history efforts such as lack of source citations, but in some cases, as I noted above, the information preserved is unique and not readily available from any other source.
Given the fact that many online collections, particularly commercial subscription sites, claim millions and even billions of records, it may seem that this collection of 38,000 plus items is marginal. But if you realize that these items are only now, for the first time, being digitized, then you can begin to see the impact this collection will ultimately have. For example, I chose the following book at random from the Archive:
The Alward family : from manuscript and notes contained in a file in possession of the compiler
I did a search in WorldCat.org for the item and there was no result. No other major library apparently has this book. I believe that a significant number of these books and manuscripts are available only the in the specific library contributing the item to the Family History Archive.