Plain-view obfuscation techniques

I often send information that I don't need to protect from anyone but casual viewers:

• hackerspeak - a way of exchanging similar-looking characters ("E"s into 3, "W"s into \/\/)
  
• teh srclamber tool - benefits from the fact that we don't really read entire words, just the first and last character
  
• rot13 - an ancient technique of rotating everything 13 characters forward (and then backward by the recipient)