I've done some recent updating of my newspaper page, in preparation for a talk I gave this week. And I was happy to read on Eastman's Online Genealogy blog that the first of the newspapers scanned in the National Digital Newspaper Program are now online. NDNP is a successor of sorts to the United States Newspaper Project, which was responsible for getting thousands of newspapers microfilmed. When I went to the site to check it out -- Chronicling America: Historic American Newspapers -- I was happily surprised to find they offer a directory of newspapers published in the U.S. I suspect it is an updated version of Gregory's American Newspapers 1821-1936: A Union List of Files Available in the United States and Canada, but it doesn't say that.
While I am grateful for all the newspapers now being made available digitally, the current situation is quite frustrating.
First, it is extremely difficult to find what has been published digitally. You must check such a variety of subscription databases. And even if you have access to several or all of them, checking is not easy because they are constantly updated, so each time you check, you find everything you already found, plus what is new. If only there were a way to limit these searches to content added after a certain date. Ideally, of course, they would recognize you and offer to check for new content only.
Another problem is that OCR (optical character recognition) that allows us to search for any and all words in the publication simply can't be accurate on the quality of print found in newspapers -- especially very old, microfilmed newspapers. So there are a LOT of false hits. Lots and lots of false hits. And probably some misses that we'll never know about. The software does seem to err on the side of caution, looking for anything that might even conceivably be construed as the letters you are looking for.
And finally, even with millions and millions of pages being posted, it is still drop in the bucket. Your chances of finding the very newspaper for the time period you need are quite slim, even if you are willing to pay subscription costs (oruse the large libraries which are willing to pay for the newspaper electronic resources so as to have them available to patrons), as well as scour the intranet to see what is provided for free.
The final word: for much of our research we will still have to order the microfilmed copies on interlibrary loan and go through the pages one by one to find the information we seek.