This question interests me because the information profession (and libraries in particular) has its own jargon. I remember writing in a monthly report to my boss -- a corporate manager -- that the library was doing a "retrospective conversion." As a non-librarian, my boss had no idea what I was talking about. In the same vain, people who are not involved in digitization projects do not know what the word "digitization" means. So if they are not familiar with this concept, how do they locate projects that would be useful to them? In other words, must they know the terms "digitization" or "digital library"?
I haven't done a study of this, but from the searching I do, I suspect that if someone knows the terminology used by digitization projects, one has an easier time finding projects on specific subjects. However, if one is unfamiliar with digitization projects, finding one project of interest might be like finding a needle in a haystack. This haystack gets even bigger when you realize that most people do not search effectively. Gary Price notes in an article written for Search Engine Watch that people average two words per query and two queries per session. In addition, people only look at the first page of search results. An article in the August issue of Information Outlook noted that people use the same term to describe a concept, item or object less than 20 percent of the time. So if people use only two terms and people don't use the same two terms, and don't realize that they should be looking for a digitization project, how will they find your project?
Of course, the answer is lots of metadata, however, in creating that metadata you must think of ALL the terms and related terms that a person might use to describe your project. Given that there are limits to how much metadata can be used, you will need to select the terms you use carefully. It would be helpful to ask potential users to think of words that might use to find a site such as yours. (Or how would they describe your site, subject or project?) It might also be useful to ask how they would spell those words. You might find that people aren't spelling terms as you assume (i.e., correctly), therefore you might want to add a common misspelling to your metadata. And since search engines might also index the text on various pages, you'll need to ensure that the text is descriptive. For example, instead of just saying "this picture", you might briefly describe the picture ("this picture of a Mayan temple..."). With the increased amount of text and metadata, we can hope that searchers will use some of the same terms/text and that the site will appear on the first page of results.
If you ask for feedback from users (e.g., though online forms), you might ask how people found your site. If they found it through a search engine, consider asking what terms they used for their search. Any information you gather could help you modify your metadata and text to be more effective.
In the end, a digitization project is successful if people use it. So helping people find your project is important. Your metadata and text are the keys to making that happen.