We are building something like that, for all the fields out there. We've built an interest graph that allows for it to the targeting to be hyper-relevant that really gets at exactly what you are interested in (so what era/region/aspect of history rather than just 'history').
We are launching our beta in the next couple of months, but until then you can sign up on http://shuffle.do to stay tuned. Happy to answer any questions.
We are launching our beta in the next couple of months, but until then you can sign up on http://shuffle.do to stay tuned. Happy to answer any questions.