The great thing about Go Historic is how comprehensive it is, and how many different ways it allows you to search for different places. If you have a particular place in mind you want to learn more about, you can type it in the search box at the top, or, if you're looking for places to photograph in a specific area, you can zoom in on their map. Each entry on the Go Historic site features photos (if applicable), several different zoom levels, links to maps, and information about the site.
(I told you it was comprehensive!)
As promising as Go Historic seems to be, it still has a few kinks to work out. For one thing, several of the links seem to be broken. They have a wonderful section about historic people but I can't seem to click on any of the names. Also, some of the map data is inaccurate. I was looking up an historic site in upstate New York, and it placed it on the map in Manhattan. When I clicked on the link to the Google Map, it took me to a spot in another country. This happened with a couple of the sites I looked up, but with others, I had no problem. I am hopeful that since the site is still in beta, that these problems will be fixed shortly.
In short, Go Historic seems like a great site with lots of potential. Do you think you'll be using Go Historic to scout out new locations to photograph? I know I already am!