In Michael Rogers' technological innovation keynote he asserts that it's always good to look back at least as far as you look ahead. In this specific case, he's looking at technology trends both past and present.
Rogers starts the keynote address by looking back at where technology was in 2002 before looking forward to 2020. He points out that a 24" LCD TV cost $7,000 and encyclopedias had just arrived on CD-ROM. For the rest of the keynote, he talks about what's next in technology.
Rogers explains Metcalf's law which says that the value of a network grows as a square of the number of nodes. He gives an example of the fax machine, which was around for years before it finally took off. And when it did take off, it was because enough people had fax machines to make it worth it to get one.