Censoring email

It seems some mail to Apple’s iCloud has been caught in filters. Apparently, a few months ago someone sent a script to a iCloud user that contained the phrase “barely legal teen” and Apple’s filters ate it.
The amount of hysteria that I’ve seen in some places about this, though, seems excessive. One of my favorite quotes was from MacWorld and just tells me that many of the people reporting on filtering have no idea how filters really work.

And it’s not as if there’s a lack of good, free email providers with years of spam-blocking experience: Google, Yahoo, and Microsoft all spring immediately to mind. And—as far as we know, anyway—those services aren’t “helpfully” blocking any emails without telling their users.

“As far as [you] know” isn’t very far, actually. These services block email all the time and normally don’t tell users about it. Hotmail is notorious for accepting email and then just silently dropping it on the floor. Yahoo doesn’t usually drop mail after it’s been accepted, but is very picky about what mail it accepts. About the only company mentioned that accepts everything is Gmail. And even then I know Gmail does, very rarely, block at the IP level.
Filters are complex and filters are extensive. I hate it when filters are responsible for losing legitimate mail but it happens. I’m pretty sure, though, that outside of the testing for the phrase “barely legal teen” that this is a filter phrase that has an extremely low false positive rate.
That’s the crux of what’s useful in filters: how much bad mail does this stop while letting as much good mail as possible through. If a particular filter catches lots of spam, and blocks only a tiny bit of real mail, it will be a useful filter. If it doesn’t catch much spam but also doesn’t block much real mail, it might be a useful filter. If it catches too much real mail, it’s not a useful filter.
As it is, Apple and their filtering vendor have adjusted their filters such that mail with the phrase “barely legal teen” is again making it into the inbox.
I’m not really sure this is a win.