First, please don't use hashkernel in production. It's a toy designed to showcase how hash kernels can help us (easily) learn on structured data. VW is faster,

First, please don't use hashkernel in production. It's a toy designed to showcase how hash kernels can help us (easily) learn on structured data. VW is faster, smarter, and more featureful. However, it doesn't know how to learn on structured data.