For example: my little brother has been buying and selling things on e-commerce sites. He finds arbitrage opportunities. He sees that something is being sold on one site for less than the going rate on another site and takes advantage of the opportunity. I was thinking that there should be some sort of web crawler that finds these arbitrage opportunities. 1) Does it exist? 2) If not, why not? Is it a good idea? Is it technically feasible?
HN would be the perfect place to discuss things like this because of the strong community.
Note: I already posted this in the feature request section (https://github.com/HackerNews/HN/issues/121), but it didn't get much attention and I think it's important, so hopefully it'll get more traction here.