This week, Apple held its yearly iPhone event, and for the first time ever it introduced two new iPhones—the 5C and the 5S. What's the difference between the two?

Let's start with the iPhone 5C. Essentially nothing more than an iPhone 5 repackaged in colorful, plastic enclosures, but with a lower price point (starting at $99).

The new model will open up the iPhone to users around the world who are more sensitive to price, which is great news for developers and brands because it means more iOS app users overall.

What else do marketers need to know?

Apple kicked hardware up a notch with the iPhone 5S.

The new A7 processor is a significant leap in processing technology for Apple's mobile platform, with power that sets up the landscape for iPhone apps to push the limit of what's possible.

For the first time, Apple also included a second processor—the M7. This low-power processor is specifically designed to collect data from various sensors on the iPhone to track the movement of the person carrying the device. Apparently, Nike's already paying attention.

As iPhones stake their claim in the wearable space, the M7 opens up a whole new class of applications that use this technology.

Point-and-shoot cameras should also take note that Apple's coming for them. With improvements to the aperture, the flash capabilities, and the sensor itself, the 5S sets a new standard for phone photography.

Finally, Apple introduced Touch ID—a new security feature that takes your fingerprint and makes it your password for your device. In the long term, developers will be clamoring to access this technology, as it opens opportunities to create rich experiences around retail and the mobile wallet.