Over on blink-dev, we've been discussing  adding a property to navigator that reports the number of cores . As far as I can tell, this functionality exists in every other platform (including iOS and Android). Some of the use cases for this feature have been discussed previously on this mailing list  and rejected in favor of a more complex system, perhaps similar to Grand Central Dispatch . Others have raised concerns that exposing the number of cores could lead to increased fidelity of fingerprinting .
My view is that the fingerprinting risks are minimal. This information is already available to web sites that wish to spend a few seconds probing your machine . Obviously, exposing this property makes that easier and more accurate, which is why it's useful for developers. IMHO, a more complex worker pool system would be valuable, but most systems that have such a worker pool system also report the number of hardware threads available. Examples: C++: std::thread::hardware_concurrency(); Win32: GetSystemInfo returns dwNumberOfProcessors POSIX: sysctl returns HW_AVAILCPU or HW_NCPU Java: Runtime.getRuntime().availableProcessors(); Python: multiprocessing.cpu_count() In fact, the web was the only platform I could find that didn't make the number of cores available to developers. Adam  https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/B6pQClqfCp4  http://wiki.whatwg.org/wiki/NavigatorCores  http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-November/024251.html  http://en.wikipedia.org/wiki/Grand_Central_Dispatch  https://groups.google.com/a/chromium.org/d/msg/blink-dev/B6pQClqfCp4/bfPhYPPQqwYJ  http://wg.oftn.org/projects/core-estimator/demo/