I am used to Chrome's tab to search. For example, whether it's YouTube, Amazon, Wikipedia, or any other site with its own search function, all I have to do is start typing "yout," Chrome will automatically fill it out to youtube.com with an option to press Tab to automatically start searching youtube from the address bar. https://support.cdn.mozilla.net/media/uploads/images/2017-09-30-04-22-57-d66d66.png https://support.cdn.mozilla.net/media/uploads/images/2017-09-30-04-23-01-36f721.png I am aware of keyword search, which is a okay workaroud for some sites, but I can't set and remember all keywords for maybe 20 sites. It would be really nice, to quickly search in a website, by typing the websites name and then tabbing (or some other key) I'd be willing to implement this feature.

Please move to bug 782557. You can ask Florian about the implementation effort, he's the Search owner and can help you coordinate. I think in general we may want this feature for parity and easier users onboarding.