Have you tried GMail Autopilot?

I always lie. My mother told me to - Spotted on a T-shirt

Google continues the tradition of perpetrating April Fools' Day hoaxes.

Considering that most GMail Labs features are unusual, I fell for the Autopilot hoax. After all the Text Stats feature in Amazon and the email analytics feature in Xobni do a somewhat similar job of mining information from text and user behavior. Although I wouldn't want a program to send personal emails (an idea as ludicrous as the "modern" feeding machine in Charlie Chaplin's Modern Times or the story writing machine in R K Narayan's "The Vendor of Sweets"), the idea of mining emails to derive practical or psychological results from messages appealed to me.

I've sometimes found the sneaky "There are unused icons on your desktop" popup balloon in Windows XP and AutoArchive feature in Office Outlook useful. I both marvel at similar intelligent features like Spam Filters and fear about any negative consequences bought about by an inhuman automaton in scenarios not imagined by it's creator.

So, what friendly spying software do you find annoying or likable?