It is basically a search engine for sites you like. Add (they call it “historify”) a site using their bookmarklet, their browser extensions or manually, then come back to the site and search your historified sites just by entering some keywords!
Historypin is the place where people come together to share their historical pictures and stories. Together we want to collect old photos to build up a digital history of the world. Explore Google Maps through an extra dimension, time.
TimeRime.com is an online community that allows people to create, compare and upload information by creating timelines, and to view information uploaded by others. Information can be uploaded by individuals, as well as companies or (public) institutions.