I consult a sh#tload of aggregators, all of them involving at least some kind of web-scraping, most of the time quite a lot of the data-sources were not asked d

I consult a sh#tload of aggregators, all of them involving at least some kind of web-scraping, most of the time quite a lot of the data-sources were not asked directly for their approval. The simple formula is: "Create more value than you take." - read it as "Create more value for those whom you take from than the value you actually take from them." If you scrap sport results from a sports page and create a competing product, as#hole move, don't do it and you will sued anyway. Scrap sport results from a sport page, aggregate them into nice charts, but for detailed inspection the user has to go to the source (which you link to and want the user to use), you are good to go (from a product point of view, legally i.a.n.a.l). The internet is not a zero-sum-game. Building on top of each other, even on data on top of each other, will lead to a better ecosystem, to more value for every participant.