Follow along with the video below to see how to install our site as a web app on your home screen.
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You can read about Windows Home Server here:
http://en.wikipedia.org/wiki/Windows_Home_Server
There's a link to the 2011 version with the changes.
Windows 7 wiki is here:
http://en.wikipedia.org/wiki/Windows_7
If you just want a box that has a shared drive that you can copy files to, then Windows 7 is all you need. If you want a box that has a client-server relationship, user accounts, shared storage, etc., then you want WHS.
I would go with WHS. It's very simple to use.