Spanish for "Always Green". Refers to the gTalk property by which a person is always online and always active status, either because said person uses a blackberry, or an IM client that doesn't change their status.
When working from home, siempre verde can be used to trick your boss into thinking your sitting at your computer, when in fact you are drinking.
"Mike, it's noon shouldn't you be at work instead of at this liquor store?"
"I AM at work... siempre verde baby