BigString.com - How does it work?
 

http://www.bigstring.com/

Lets you recall, or change, sent emails.. even if they've already been read by the recipient. Can make pics destructable, unforwardable & unprintable.

How does this work??

hmmm this is new to me, I don't think it's of much use though do you?

msgs and imgs are probably stored on their system, mailbody is probably replaced with something else when requested.

AOL and a few other ISPS have been doing similar things for AOL to AOL mail, GI is non retractable..