I see some decent points in the post, but they are mostly about modelling. What I'd like to say is even though you have a good model, that doesn't tell you wha

I see some decent points in the post, but they are mostly about modelling. What I'd like to say is even though you have a good model, that doesn't tell you what to do. If you know it's going to rain next week, should you go corner the umbrella market? If you are going down that route, there are a bunch of non-weather things that you'll need to know. Perhaps where to find a cheap source of umbrellas, likely places where people will be the most susceptible to buying, and so on. Basically domain expertise. The major issue you will have is whether your own presence causes your model to be inapplicable. If a guy sees you at the umbrella factory, maybe he will decide that's a signal that the weather will rain next week? Maybe people will just stay home in that case? The main thing I see with Zillow is a lack of due diligence. There seems to have been an idea that you can just have some data people, pour in data, and out comes money. In reality there's a lot of legwork in any business, and you pay for experience with money. In this case also your job.