Here’s a site than will be useful for both teachers and learners of pre-school, elementary and high-school. 42explore.com is in a way a link library that nucleates those links into areas of interests: General themes, Social Studies, Science, Math, English, Health & Fitness, Fine arts and Applied Arts. The reason as to why they are divided into those areas is that the site is supposed to help students develop school projects, so aggregating all the content in subjects is a good way to get them thinking. For every specific topic there are several listed sites, so users can adequately learn to investigate by comparing and contrasting information and data sources. But it seems to me that is useful in regards to particularly lively and motivated students; another possible audience –my guess is that this is the largest percentage of users— would be teachers, who will most probably be very benefited by the concise and organized information available from the site when planning their lessons. Other than the resources directly available from the site, the two teachers responsible for it have published a series of books on teaching and using the web as a teaching resource, which can be bought directly from the site.