Tumbleweeds are a common feature of
desolate, quiet places (in the movies, anyway). Also, there's a sense of
foreboding that tumbleweeds bring to any mental image - they're almost
surreal.
Ominous sky, sound of the wind, tumbleweeds drifting by...
Whenever the chatterbox has been quiet for a while, I generally make some reference to tumbleweeds. To me, it's more entertaining than EDB (that got old after about a week), and it accurately represents how Everything "feels" to me at the time - dead, desolate, ominous. Sure, it probably just means everyone is busy noding, but the feeling that you are somehow "connected" or in contact with other people is missing. When the Chatterbox is empty, E2 seems more like a database and less like a community. In reality, it's both, and so it's quietly disturbing when one aspect is missing.
And certainly a landscape worthy of its fair share of tumbleweeds.