Siri isn't sending anything to anyone. I think that's his point. Siri added a task to a calendar, just like she has always "known" how to do.

Yep. Simple CalDav sync from the calendar. Nothing is new on the Siri end.

You tell Siri to add a task, and then it shows up in this other thing. You can quibble about just which entity is doing the sending, but that seems even more pointless than quibbling over "taught".

My quibble isnt with the word "taught", but rather with the overall wording conveyed in the title. As it is now, it seems to suggest that they've uncovered a hidden API where you can add custom grammars to Siri. A more accurate title would be, "RTM can sync with your iphone calendar". It really has little to do with Siri itself. Any calendar task will be synced, not just ones created by Siri.

in my opinion, "taught" seems to imply that siri can actively learn. though siri is an intelligent agent which does speech recognition (firmly planting it in the world of AI), i am under the impression that siri does not actively learn and so saying "taught" in the context of speaking about an AI could be construed as misleading. i could be mistaken about whether siri can do "learning" or not, as i'm not intimately familiar with the tech.

Why it didn't send task to RTM before is something that needs investigation. Probably a task <-> RTM synchronization failure.