Just when I thought I had invented something revolutionary, a Google search deflates the sails. Ever send an email saying "The file you asked for is attached." Then press send and go "oh crap" and send a second message, with the file? Or worse yet, wait hours then get a confused message back: "you forgot the attachment".
In computational linguistics we are obsessed with evermore complex analyses of language, but a simple keyword spotting algorithm could help millions of people remember their attachments. Just scan for the prefix "attach" and warn the user attempts to send without any attachment.
Turns out a couple of people have made Thunderbird extensions that do this. Too bad I just switched to managing all my mail with Gmail. Why don't all the providers do this simple trick? It could be enhanced to work very well with some simple language models (e.g. ignore "attachment" if it modifies another noun like "hose attachment", ignore "attach" if it appears in quotes, etc.).