Multitasking was probably the biggest announcement – take that ‘droid.. JK. Rather than just do multitasking as a one size fits all model, there are number of background API flavors that attempt to address the different background needs of different types of apps – telephony, music, geo-location, push notifications, etc. This is clearly driven by the need to control the battery consumption.

App developers will have to pick and choose between the various APIs to see what ones fit their app. Not all APIs will apply to every app, but clearly for apps like Pandora, Maps/Location, Skype and others, these APIs make those apps first class citizens on the OS level the way music, mail and phone Apple apps are.

It’s not true multitasking like you can find on Unix. It’s a controlled multi-tasking API. It puts the onus on the developer to use the API’s in ways that enhance the app. Poor implementation will drain battery life but it won’t be because of the OS, it’ll be an app developer issue.

There are a number of other focus items like iBooks for the iPhone, unified InBox for mail, better enterprise integration and a game developers quasi-social network, and a quite a number of small items updated in the OS.

The other item worth mentioning is iAd – Apple’s interesting twist on mobile ads. I love this from Steve:

When you look at ads on a phone, it’s not like a desktop. On a desktop, search is where it’s at. But on mobile devices, that hasn’t happened. Search is not happening on phones; people are using apps. And this is where the opportunity is to deliver advertising is.

Apple’s iAd APIs will allow developers to plug into an Apple controlled ad network in order to support apps. This is in response to the proliferation of free apps supported by a multitude of different ad networks. Apple’s willing to do a 60/40 split w/the the developer. Apple’s got an interesting interactive ad model where ads can be as rich as the app they are running in. There are too many details to explain on how the iAds can work, but I’m sure Apple will post demos on how rich they can be. Users could get lost in them thinking they were apps themselves.

More importantly, Apple’s taking aim right at Google’s ad system and Flash in 1 stroke. By creating a whole new way to develop interactive ads and a distribution network, the wind goes somewhat out of the “Flash on the iPhone” sails and Google’s no longer the easiest way to distribute the ad. This will be interesting to watch.

Update:

Daring Fireball has a post on a change in language of the Developer Agreement that bans cross compilation techniques for iPod/iPad/iPod Touch apps. If it wasn’t clear that Apple is at war with Adobe/Flash it is now. I’m guessing that Flash CS5 is toast on Apple mobile devices.

Launchd has several “modes” that it can launch an “agent” in. I was telling launchd to run my program in the wrong mode. I had to add a  LimitLoadToSessionType key set to Aqua to the configuration file that I fed to launchctl and call launchctl using “-S Aqua” option. There was much rejoicing! Before the program was trying to read the default system keychain, but with the “Aqua” setting, it used the user’s default, which is what I wanted.

If you’re using launchd, this little doc is your friend!