What's a good tool for sharing resources & tutorials among team members?

Not sure if something like this exists, but I'm looking for a simple tool to share images, files, code snippets, links and also be able to write short notes so everyone on the team can have access to it. Should not be limited to one project only. E.g. I would like to write a brief note with some steps on how to configure a web server and have a place to store it so other team members can find it later. It's like Gist for snippets, but not only limited to code snippets. Should have an easy and simple way of searching (tags or keywords?) As a plus, would be great to include markdown support! Does anyone know something like that?
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