This is a bit different compared to the rest of my education-related links, but this can be a great resource for a teacher or student who has a product that they wish to promote on the internet.
AwesomeStories is a gathering place of primary-source information. Its purpose - since the site was first launched in 1999 - is to help educators and individuals find original sources, located at national archives, libraries, universities, museums, historical societies and government-created web sites.