Wow, Siri is pretty awesome. I've probably opened the alarm/timer app for the last time. Just say "Set a timer for 15 minutes" and that's it. There may be more and more apps I don't open too.
I assume they're doing the next thing: getting statistics about they types of things people ask about and where Siri doesn't have the answer. Recipes? Movies? Travel? Then partner with someone to provide the answer rather than having to send it as a search off to Google.
That's one less thing Google gets to show ads for, which has to be pretty huge for Apple.
And that's a very valuable customer recommendation, companies may pay huge money or give a commission for the privilege to being Siri's answer. If all movie questions got sent to Fandango, or all travel requests went to Expedia, wouldn't they give Apple something for that? If I were them I would give a LOT for that.