When you're a humanoid of very little brain, any help you can get with remembering things is welcome.
Any help fighting the discomfort of deja vu is even better.
Today's Best of Linux helps you figure out why what you're doing seems so familiar. The Remembrance Agent keeps track of what you've written in the past, and relates it to what you're writing now. First, you have to let it know about your previous work by giving it a list of files and directories to catalog. It searches them, indexing the files and recursively indexing all subdirectories. The next time you fire up Emacs, you can turn on Remembrance Agent, and while you work, a separate window provides a continually-updated list of other files which are related to what you're currently writing.