A while ago I wrote briefly on why the Singularity might not be near and my estimates badly off. I saw it linked the other day, and realized that pessimism seemed to be trendy lately, which meant I ought to work on why one might be optimistic instead: http://www.gwern.net/Mistakes#counter-point
(Summary: long-sought AI goals have been recently achieved, global economic growth & political stability continues, and some resource crunches have turned into surpluses - all contrary to long-standing pessimistic forecasts.)
It's hard to apply until people can afford to be tested. When more people are tested, network effects become possible. And I thought I saw a recent article about successful use in the context of cancer research - scan normal and cancerous cells, and find the difference. There've been those kind of article for years, but this one showed a success.
Also, the fabrication of manipulation of DNA is just getting off the ground. When life forms can be routinely programmed and tested, we're likely to see some very interesting and useful results.
Watson just won, and they're starting to turn his attention to less trivial questions.
All the life science XPrizes are amazing.
You've pointed out some of the improvements in online learning. One big boost to AI progress will be the hundreds of thousands getting AI training online.
Singularity? Don't know and don't care. Technological progress - immense and accelerating.