Headup is a new plugin for Firefox that uses semantic web methods to produce personalised data related to the current webpage from all over the web. It's been defined as a "personal discovery agent to the web", an intelligent search agent basically. It uses Silverlight 2 to store information locally so that privacy isn't an issue.
It's in beta right now, but you can request an invite, it won't be launched until early next year.
It supports Digg, Gmail, Google, Wikipedia and some others. It also has geolocation capabilities through Yahoo.
This is the kind of thing that I have been seeing increasingly in the last 2 years, with systems that can replace the usual search results browsing by delivering a wealth of information directly to the user.
These intelligent agents are AI entities which act upon their environment and observe changes and patterns. They learn from their environment and gather knowledge. They use this information to fulfill their duty, in this case providing relevant information to users.
Nicholas Negroponte (one laptop per child project, and head of MIT Media labs) wrote a book in the early 90's about creating a more human environment. This idea has been around for a while now, and there is research being actively carried out in this area.
It changes the SEO landscape quite significantly, because information pertinent to the user's information needs comes from all over the place, rather than from the search engine exclusively. What would happen if this became widespread? Visibility on the web becomes a very important issue for companies. The social media marketing trend would probably become set in concrete as it were. Getting people through to sites through many different places than simply search engines becomes important. And what becomes of the search engine? Do they become back-end systems?
Check out Headup and see what you think.