well, that's really not the reason i didn't do it. amongst other things (my lack of preparation at the time, primarily) it just wasn't easy for anyone but a few big companies because the biggest requirement is that you have not only scale, but loads of data. this is no longer true. you now have aws, hadoop, etc, so it's easier and cheaper to scale, but this is why i knew google would do it. they had the capacity, and they still do. very smart machine learners, petabytes of data, scale, etc.