I stumbled upon this topic when I was scrolling across this forum.
I did some research and WebCL seems like an interesting idea.
My first impression was that it would be nice to give web developers the option to utilize the power of GPUs and Multi-core CPUs with their web applications and offering this sort of power could yeild intersting sites on the web. After my research, my second impression is that, will there be enough support for it?
From looking at the page on http://webcl.nokiaresearch.com/index.html it seems like you need to download the latest version of a very specific browser on very specific OSes and install third party extensions. I understand that right now WebCL is expiremental, and in time it could be adopted by web browsers. However, if it is to be a useful tool to web developers, it needs to have ubiquitous, native, web browser support. In otherwords it needs to be automatically supported by all major web browsers.
I read a report recently that Microsoft wont support WebGL because of security issues. Will WebCL recieve the same treatment? IE currently has the highest browser marketshare (although it's losing it slowly). If a technology isn't supported by IE, even today, usually it isn't utilized by most web developers from fear of not reaching a large share of the web.
WebCL is dependent on both software and hardware, it's going to need relatively recent hardware and a really new web browser to be able to be utlilized. The web serves a wide range of people, there are people on netbooks with atom processors to people with high end gaming rigs with a Core i7 and a GTX 590. There are people still using IE 6 and thouse who don't know what a browser is to people who download the lastest beta of a browser the moment it comes out. Web experience provided by webCL is going to vary widely between different groups of people. It might not be attractive to developers for some time because of this.
It seems to me like WebCL is a good idea, but it's years ahead of its time.