Spam filter augmentation proposal

I was thinking of augmenting my spam filter to also reject:

  1. messages that don't use punctuation
  2. messages that include questions with periods at the end
  3. messages in ALL CAPS
  4. messages with a question mark to 80-character-line ratio >= 1
  5. messages containing "u", "u r", "ur", or "lol"

That would be awesome.