WebCL is important because it not only brings supercomputing to the desktop but into the web page. Samsung has a first release for WebKit and some impressive demos of its potential.
WebCL is a new standard that is being developed by the Khronos group, the people who make WebGL the web based 3D graphics standard a reality.
WebCL is being designed as a way to make use of OpenCL on the Web. OpenCL is a framework, developed mostly by Apple and later NVIDIA, that lets software make use of a GPU for normal computing operations. Both OpenCL and WebCL are open standards.
The video below shows the amazing speedup in moving from a CPU based implementation of a simulation through a CPU/GPU and finally GPU/GPU based simulation. Notice that this isn't just a matter of making a minor change. To make use of the GPU the computational code had to be re-written in a parallel form.
At the moment the only problem with the move to parallel code based on the GPU in web browsers is the simple fact that Microsoft refuses to include even the WebGL standard on security grounds in IE9 or IE10. It is likely that Microsoft is working on its own 3D and GPU computational system based on DirectX but at the moment there is no real information apart from the lack of support for WebGL and WebCL.