I started using iPython Notebook from Chrome at port http://localhost:8890/ and found that the keyboard shortcuts were not working.
Searched for “iPython Notebook clashing with Chrome” but got no useful results.
Finally, figured out that the problem was that I had Vimium installed on Chrome (I always do that first when installing Chrome — it adds Vim like capability to Chrome)
Turning off Vimium just for IP-s pointing to iPython Notebook now lets me access the Notebook shortcuts (see entry for http://localhost:88*/* in Vimium settings below). Woohoo!
On the fly deactivation of Vimium may also be a solution.