Talk about a culture cache, a great place to find primary sources and an outstanding historical resource for the classroom… The New York Times’ Time Machine caught my eye on a feed of education-related links.
What can you use it for? Well, to start off, feel for yourself how eerie it is to read the day-of accounts of Lincoln’s assassination. Download them in .pdf. Read what else was on people’s minds that day. For discussion, compare/contrast the design of what today’s newspapers look like compared to what people paid only for cents to read back in the day.
Drawbacks? Well, NYT would still like to make subscription money, so you won’t see any newspapers beyond the 1920s yet. However, I’d suggest that they really consider adding a World War II archive pretty soon, seeing as I remember that topic being one of the most-studied wars in my school career.