Yet more possible (or current) breakthroughes in technology together with a very basic description, critique, likelihood and timescale.
Development: High capacity hard drives >10 terrabites
Importance: All the (English alphabet) text in all the books in the British library would fit on a drive with 10 terrabites of storage. With this technology there would be the potential to give billions of people access to almost everything that has ever been written. The pace of scientific, technological discovery as well as the literary prospects are staggering.
Drawbacks: Copyright infringement.
Time scale: A decade.
Development: Thin film dye solar cells.
Likelihood: Currently being commercialized.
Importance: By reducing the cost of a solar panel by as much as ten times these devices could make solar power competitive with coal. The potential to reduce our dependence on fossil fuels will make preventing catastrophic climate change that much easier.
Drawbacks: The dyes used degrade too fast under sunlight. The MIT scientists working on this think the rate of degradation can be sufficiently reduced so that the solar cells would have decades of useful life.
Time scale: 3-5 years.