Kincy just forwarded me a call to the WWDC conference, the Apple developer conference coming up in June.
The image on the ad is the following:

Now, what this shows is the Notes application of the iPhone used to add a Task...
You can read this in two ways:
- The person who prepared the ad tried to find the Task application on the iPhone. Since it was not there, s/he decided to use Notes instead. Who cares about usability? This is Apple after all...
- Apple is desperately in need of a developer who will write a Task application for the iPhone. The ad is a teaser for developers: "we left Tasks out so you can show the world how smart you are, come and develop it"