Via Seb, who could have combined the previous post with this fascinating description of a synchronicity engine:
"Something needs to capture way more channels of information about you than you normally bother paying conscious attention to. At least not at the same time. What people have been saying around you recently; what clothes you're wearing; what's on your bookshelf; all the people you know; all the subjects you're interested in; all the projects you're working on. And something needs to be matching all these items with other people's items, and items in your surroundings, as a background process."