Well you have the "last here at" stamp. I don't think it will cause much of a hit on the db for an extra possible field per home node/scratch pad, and I think the idea has merit.

On that note ( I should look and see if this is done already ), it would be nice to have a token so that when updateing a home node or pad, you could insert a stamp.. like $DATE$ or somesuch.

Just a thought and a vote in favor of stamping pads