Privacy is becoming more an issue as computers are shared between different people, all of whom have files they might not want to share with each other.

Setting up user accounts helps to a certain extent, especially if the option to keep files private is enabled.

Scrambling the contents of files with encryption is an effective way if you want to be sure that private files stay that way. There's a quick round up over at LifeHacker.

Of course there are disadvantages to encrypting files. If other people do have access to those files and realise that they are encrypted they may think you have something to hide, even if you don't or it is information about their birthday present. And that might lead to even more difficult conversations.