EZGram: Write a Letter Online
This is brilliant. No stamps, no envelopes, no searching for mail boxes! The only thing this doesn't have is a signature, I guess, but it's still pretty awesome for those things you have to do by postal mail.
I just realized how weird it is that I'm willing to spend 59 extra cents just so I don't have to remember to walk over to the mailbox and drop in my piece of mail at work (20 feet away from my desk) and sms my postage payment. My value system is sort of screwed up.