Every time Facebook launches a new feature (such as Places, or Questions), they seem to add a few new categories for e-mail notification.
The problem with this is that these new notifications are always enabled by default, forcing me to go back to their settings page and uncheck a bunch of checkboxes again.
So, while I haven't been able to solve the problem of being opted in whenever they launch something new, I wrote a little bookmarklet to uncheck every checkbox on a web page. This is useful when dealing with the notifications settings page on Facebook which is starting to have many, many checkboxes.
Try it out: All Checks Off
(just drag this link to your bookmarks bar, or if you're using IE, right-click and save to your Favorites bar)
You can try it out here: