A geeky definition could be:

"An ubiquitous appliance that performs well a clearly defined task...
easy and intuitive to operate, requiring little maintenance."

Delicious lightly burned bread, mmm... perfect everytime.

Technology should be about users, not the other way around. Today's knowledge tools are slightly more involved than toasters, but should aspire to be as intuitive and easy to use.

Mail messages that appear to come from you or someone in your organization...A likely possibility is that you have been joe-jobbed... more or yet more

Check the originating mailserver in the message headers... if it's not yours, you did not send it. Unfortunately, there's nothing you can do about it. For most - unlike the gentleman at the first link above - being joe-jobbed is annoying, but essentially harmless.