A longer version of this post originally appeared on AllThingsD. Forrester clients can access the full report and the data it’s based on here.

Imagine providing essential information to your customers, in the exact time and place where they need it — and delivering that information right in front of their eyes, where they can’t miss it. That’s the vision of marketing on Google Glass. Marketers must think differently about Glass than they do about their Web or smartphone applications. And they should start thinking now about Glass, even though the device likely won’t be shipping to consumers before 2014. Here are the main takeaways from the report:

  • Glass Will Be The Next iPhone—But Today It’s A Newton. Google Glass is a "when," not "if" product. The prototype version of Glass that’s currently available to developers, known as the Glass Explorer edition, shows enough promise that we think it's just a matter of time until Glass takes off. However, its short battery life, as well as the limited Mirror application programming interface (API), which restricts app developers’ access to the device’s native hardware sensors, makes version 1 Glass more of a Newton than an iPhone. By that, we mean that Glass is extremely compelling but extremely limited in its current form, just as Apple’s Newton was. But Glass is continuously improving via over-the-air updates and new applications, and we have no doubt that in time, Glass will be the next iPhone — the next great platform for engaging consumers and workers.
  • Glass Requires A New Interaction Model. The basic interaction model for Glass is via "timeline cards": Timeline cards display content, such as text, location-based information, and media; swiping forward and backward shows cards in the order they were created or used. You can think of it as a filmstrip — going backward shows earlier frames; going forward shows later frames — except that each frame or timeline card is a living object that can be updated. For marketers, this means thinking about your brand in the context of someone’s day — what essential information or utility can you provide, in what contexts, with just a few words or images? Think about Glass apps like an SMS or MMS conversation: A series of asynchronous alerts that form meaning over time. It’s not like the screen-based sandbox of a smartphone app. Your Glassware coexists with other apps on the timeline and competes for a user’s attention. As with SMS, marketers will need to be extremely thoughtful about how frequently to send alerts or updates to a user’s timeline because it’s easy to cross the line between engagement and annoyance on Glass.
  • Marketers Must Seek Permission To Engage. Glass presents a challenge for marketers: Consumers will expect marketers to deliver contextually relevant, useful experiences, but marketers have imperfect tools and systems for delivering that relevance. Google’s policies instruct developers not to "use users’ personal information for purposes beyond the limited and express purpose of your application . . . without getting specific opt-in consent from the user. Don’t sell, rent, or otherwise provide a user’s personal information to any third party without getting specific opt-in consent from the user." In other words, the Web-based targeting technologies marketers rely on have no place on Glass. The good news is that because Glass apps are permission-based, if consumers invite you to engage with them on Glass, you’ll likely know who they are anyway — you probably have an existing relationship with them, and they trust you enough to invite you to engage with them on this intimate platform. Activities (such as being in a certain location at a certain time of day) will cue targeting, rather than cookie-based navigational history. These new schemes will coexist with industry initiatives already underway to measure and target across PC and mobile using registration or personally identifiable information (PII) data (where a direct relationship exists) as the matching key or using device data and inference to make good guesses.