I'll try keep it short. Here's the scenario: We have employees all over the world performing similar work i.e. research, generating powerpoint slides, word documents, graphics, etc. Many times a lot of this previous work can be reused for another future project.

The current arrangement is email and phone calls which as you would agree is quick if you know where to look but otherwise archaic and very very inefficient.

So I am looking for software that will allow me to do the following:

1. Tag files e.g. an investor presentation on cellphone usage in kenya would be tagged investor, cellphone, kenya
2. Manage references e.g. if we read something on the internet, should be able to paste that link in some fashion and tag it as above.
3. Preferably cloud based so that it can be accessed by anybody and additionally would be nice (though NOT must) to have access levels (director, manager, everyone)
4. A nice interface that non technically savvy folks can warm up to ;)
5. A desktop app would be handy so that people don't always have to click upload or something

A tree based system is inefficient in this case because content is usually linked across branches and also people might not quite agree on one format of a tree. Tagging works around this very nicely.

What I have considered so far:

1. Evernote (for its more professional look)
2. Springpad (for its versatility with content)
3. Mendeley (this is a research manager and in some ways ideal, but i fear its limited to PDFs)

The goal is that when somebody wants to look for a document, they don't have to ask a colleague, they can just search with keywords and all relevant information shows up.

Thanks!