What Do Twitter's Annotations Mean for the Web?

Twitter announced a series of new features at its Chirp conference in April, including Twitter Places and an advertising program called Promoted Tweets.But the one that has the most potential to change the way the social network functions in fundamental ways is Annotations, which Twitter said would be rolled out in the second quarter of the year.It isn't clear exactly how Annotations will be implemented or how much control Twitter will exert over their use by outside developers, but they could extend the service in a number of interesting directions. At the same time, however, they could also create confusion in the Twitter app marketplace and cause more tension between the company and its developer community.

In a nutshell, Annotations would allow developers (and Twitter itself, of course) to add additional information to a tweet—such as a string of text, an URL, a location tag, or bits of data—without affecting its character count. In other words, such information would be metadata about the tweet or the user who posted it and would be carried along as an additional payload as it traveled through the Twitter network. Apps and services could then collect that information and filter it or make sense of it. In some ways, Annotations are like Facebook's open graph protocol, which also adds metadata to the behavior of users on certain sites when they're logged in. Just as they are with Facebook, advertisers are interested in Twitter's ability to help them target users based on their interests.

Developers and programmers such as RSS pioneer Dave Winer have been promoting the idea of Twitter metadata for some time. Winer recently described how it could improve the service if it consisted of especially relevant information—for example, any URL included in a tweet, which would remove the need for link shorteners (including the one Twitter announced recently). Metadata could also yield services based on interpreting it, tracking threaded discussions between specific users, for example, or specific topics.Such interpretation has huge potential for such things as movie and restaurant reviews, music sharing, and even purchasing behavior, most of which are already in Twitter's list of recommended data types for Annotations.

The Question of Standards

But Google (GOOG) open advocate Chris Messina warns that if Twitter doesn't handle the new feature properly, it could become a free-for-all of competing standards and markups. "I find them very intriguing," he says of Annotations, but he adds: "It could get pretty hairy with lots of noninteroperable approaches," a concern others have raised as well. For example, if more than one company wants to support payments through Annotations, but they all use proprietary ways of doing that, "getting Twitter clients and apps to actually make sense of that data will be very slow going indeed," says Messina. The Google staffer said he was encouraged, however, by the fact that Twitter was looking at supporting existing standards, such as RDFa and microformats (as well as potentially Facebook's open graph protocol).

Rohit Khare, former director of CommerceNet Labs and a key player in the "microformat" community, is also happy to see Twitter experimenting with metadata, but he is concerned about the potential impact. "I think it's important to have standards of some kind, so that services don't start adding things that change the nature of what Twitter is," he says. "For example, you don't want to have tweets where the message can't be understood without seeing the annotations." Khare says he hopes Twitter will have some rules that govern the new feature. "Hopefully they will be there as a backstop and a sponsor and a guardian of these features, but [they] will also allow developers to suggest things."

Hiten Shah, founder of KISSMetrics, says Twitter will have to walk a fine line between telling developers what to do and allowing them to experiment, given some of the tensions between the company and its developer community over the purchase of third-party apps, such as Tweetie, and the introduction of competing features. "They aren't exactly on the good side of developers right now," he says. "I think it's in their interests to put out some best practices and that sort of thing but not to be too heavy-handed about it."

If Twitter can manage to walk that line, Annotations could be a substantial benefit, particularly because Twitter could offer features to advertisers that want to track user behavior and purchasing intent. Khare thinks that while Annotations seem similar to Facebook's open graph protocol, Twitter's variation could actually be more powerful. "Twitter's is wide open, because it isn't tied to any specific activity on any specific Web page," he says. "With Twitter, I can do whatever Twitter or my client allows, whereas with Facebook, I can only do what the publisher of the page allows. Twitter Annotations could actually lead to more open services and clients that have a bunch of different features."

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Disclosure: KISSMetrics is backed by True Ventures, a venture capital firm that is an investor in the parent company of this blog, Giga Omni Media. Om Malik, founder of Giga Omni Media, is also a venture partner at True.