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Is it a good idea to come up with a Javascript-based Proof of Work system to reduce spam on forums, and other websites?

This idea would be similar to HashCash, but the computation would be based on the hash of the contents to be submitted + a seed.

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up vote 4 down vote accepted

Javascript's performance on computationally intensive tasks is... less than desirable. Which is why you talk of WebGL, but you are actually thinking of WebCL, an upcoming technology to give access to general computing features of GPU to Javascript code in Web browsers (à la OpenCL).

I see three main issues with such a proposal:

  • There is a large disparity in available computing power in client systems, especially for GPU. It will be hard to find an acceptable compromise between people with gaming PC and people with low-power tablets.

  • There is no WebGL, let alone WebCL, in Internet Explorer.

  • Proofs of work are good to deter spammers which are short on CPU. But spammers are not really short on CPU; any competent enough spammer will use a botnet with thousands of available processors.

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To counter the CPU and Javascript less than perfect match, maybe a more memory-bound Proof of Work can help? ....Even though that it is clear that a botnet is also resourceful in memory memory.... – humanityANDpeace Nov 8 '14 at 20:20

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