New Scientist has an intringuing piece about innovation, related to the fact that may we have reached a peak of innovation. It's controversial but the conclusion is based on interesting facts. Some excerpts below:

according to a new analysis, this view couldn't be more wrong: far from being in technological nirvana, we are fast approaching a new dark age. That, at least, is the conclusion of Jonathan Huebner, a physicist working at the Pentagon's Naval Air Warfare Center in China Lake, California. He says the rate of technological innovation reached a peak a century ago and has been declining ever since. (...) In an effort to find out, he plotted major innovations and scientific advances over time compared to world population, using the 7200 key innovations listed in a recently published book, The History of Science and Technology (Houghton Mifflin, 2004). The results surprised him. Rather than growing exponentially, or even keeping pace with population growth, they peaked in 1873 and have been declining ever since (see Graphs). Next, he examined the number of patents granted in the US from 1790 to the present. When he plotted the number of US patents granted per decade divided by the country's population, he found the graph peaked in 1915. (...) The global rate of innovation today, which is running at seven "important technological developments" per billion people per year, matches the rate in 1600. Despite far higher standards of education and massive R&D funding "it is more difficult now for people to develop new technology", Huebner says. (...) But today's much larger population means that the number of innovations per year will still be far higher than in medieval times. "I'm certainly not predicting that the dark ages will reoccur in 2024, if at all," he says. Nevertheless, the point at which an extrapolation of his global innovation curve hits zero suggests we have already made 85 per cent of the technologies that are economically feasible.

But why does he think this has happened? He likens the way technologies develop to a tree. "You have the trunk and major branches, covering major fields like transportation or the generation of energy," he says. "Right now we are filling out the minor branches and twigs and leaves. The major question is, are there any major branches left to discover? My feeling is we've discovered most of the major branches on the tree of technology."

I am looking foward to see the critiques... there are already coming from Kurzweil (AI/Music research) or Drexler (nanotech):

But artificial intelligence expert Ray Kurzweil - who formulated the aforementioned law - thinks Huebner has got it all wrong. "He uses an arbitrary list of about 7000 events that have no basis as a measure of innovation. If one uses arbitrary measures, the results will not be meaningful."

Eric Drexler, who dreamed up some of the key ideas underlying nanotechnology, agrees. "A more direct and detailed way to quantify technology history is to track various capabilities, such as speed of transport, data-channel bandwidth, cost of computation," he says. "Some have followed exponential trends, some have not." Drexler says nanotechnology alone will smash the barriers Huebner foresees, never mind other branches of technology

And of course, there are intermediary views:

A middle path between Huebner's warning of an imminent end to tech progress, and Kurzweil and Smart's equally imminent encounter with a silicon singularity, has been staked out by Ted Modis, a Swiss physicist and futurologist.

Modis agrees with Huebner that an exponential rate of change cannot be sustained and his findings, like Huebner's, suggest that technological change will not increase forever. But rather than expecting innovation to plummet, Modis foresees a long, slow decline that mirrors technology's climb.

I would like to see more research about this, with an historical spin, expanding the time span to a broader scale. Besides, what would be the consequences? especially in terms of social/societal terms.