It is a formal declaration issued in the event that you will pwn someone at a later date and time if you cannot presently do it. A postpwnment is normally declared when you yourself have been pwned, but do not have the time to retaliate.
Yesterday Dave totally pwned me in CS, but I was too damn tired, so I issued a postpwnment until next week.
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2million.