First up is the link that may already be a chestnut to you internet history junkies out there, but it's one of the best: Shorpy.
Minor mill on Warren Creek by Arcata, California. Mack is the engineer, taken mid 1880s. Photographer unknown –from Shorpy.com
Shorpy posts historical photos. That's it. Explanations are minimal, but often unnecessary. When I look at the pictures on Shorpy, I think about how often a few photos can tell a story way better than a 2000 word analysis.
Shorpy also runs a comics subsite which is worth checking out too. Enjoy!