I work with these kinds of technologies. On some days, they scare the daylights out of me, because of the possibility of the Singularity. It's one thing to think of continuing technological change. It's another thing for it to be happening faster than humans can possibly keep up with.
The scary possibility is human-level AI at electronic speeds, which are six to eight orders of magnitude faster. (The human brain is, of course, many orders of magnitude more parallel than any computer we can build today, but not that much more than, say, the Internet.)
So, suppose my lab succeeds in building a human-level AI one Friday around noon, and we all go off to celebrate the Nobel prizes we confidently expect, but without shutting down our computers. We come rolling back into the lab on Monday around noon, 72 hours later.
If our new AI is functioning at human levels, but 10^6 times as fast, it has had over 8200 years, subjective time, to figure out what to do next.
More than likely, it has gone completely and non-functionally insane from boredom during that time. This is why I don't actually worry about this all that much.
But suppose it actually finds ways to amuse and educate itself with electronic-speed phenomena, and makes intellectual progress during that time, including creating a community of similar creatures to interact with. By the end of the weekend, it will be somewhere unimaginable to us. (That's why they call it the "Singularity".)
With human-level intelligence (by hypothesis), and that amount of time, we certainly can't imagine limits on what it might accomplish. Perhaps it will decide to destroy humanity, or do so accidentally while learning something else. Perhaps it will just decide to leave, and we'll come back on Monday and find it gone. Perhaps it will decide to be good, or bad, or God, or something else.
As Arthur C. Clarke said, "Any sufficiently advanced technology is indistinguishable from magic." That's what the Singularity offers, and why it's scary.
Perhaps in 2050 we'll look back at this and laugh, like we laugh at the scientists at Los Alamos thinking that the first atomic bomb test might possibly ignite the atmosphere.
But perhaps not.