Thank you, that's a helpful tip! I used to use many modifiers for my Google queries, but Google dropped support for many of them, and doesn't seem to document comprehensively what they actually support from day to day.

I wish excluded keywords were the only frustration. Their index seems to have gotten considerably worse at dealing with any somewhat "long-tail" query. I'm not sure why.

I suspect they've won the spam battle by aggressively purging from their index, but in doing so they've lost the spam war because the false positive rate on their approach is way too high. Or maybe I'm completely off base.