Maybe you want to get a tweet when your laundry's done [...]
Who would actually do this? Why would I use Twitter to send a private notification like that? It's pretty much the worst system imaginable. Twitter works great for broadcasting to people, but it's nonsense for one-to-one messages.
Is this really how I want to set up my washing machine:
1) Create a Twitter account for the machine. Let's call it @pavlovs_2011_electrolux.
2) Subscribe my public Twitter account to @pavlovs_2011_electrolux. (Alternatively, maybe the washing machine can be configured with my public Twitter account so it can send messages to me.)
3) Keep an eye for my washing machine's notifications amongst a sea of disorganized tweets about public topics.