You're sat in the lounge with your family, and you want to show them your holiday videos on the Mac mini you use as a media centre. But the videos are on your iMac. How do you transfer them? Or maybe you've just finished a Keynote presentation, and need to share it with a colleague who has his own user account on your Mac. It's too big to email, so how do you get it to him? You could use a USB stick, or email smaller files to yourself. Or for your home network, you could invest in a network attached storage (NAS) drive, accessible to everyone. But there's another way. Using OS X's file-sharing abilities, you can define a folder as 'shared', enabling other computers on your network - and other user accounts on your Mac - to access them. Privileges can be set to give different access rights to different accounts, allowing people or groups to read, write or both
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