I really enjoy this feature and even catch myself regularly trying to use it on other computers, which obviously don't have such keywords defined.
I recently switched from chrome to Firefox but the search engine situation is something I’m not really happy about.
Nope, you can just right-click the site's own search bar, which is how I've been doing it forever.
Actually this is exactly what lorenzhs said, and it is my experience too. I know this because I spent half an hour trying to get a “blue search” for BBFC.
It works flawlessly in all browsers I use.
Typing "w! foo" beats "wikipedia foo" every time.
Funnily enough, I've often seen Firefox users unaware that they can do the same with custom search keywords in Chrome, so the problem runs both ways.
As someone who uses these features in both Firefox and Chrome, I do think it would be nice if Firefox copied how Chrome automatically adds these search actions, and perhaps a bit of the UI polish too (like how Chrome's omnibox will recognize you're performing a keyword search and adapt accordingly). It doesn't make much of a difference for existing power users, but it could help new users discover and use the feature.
It's still not as smooth and doesn't support as many OpenSearch providers as Chrome's, but might already help a bit.
Firefox actually has 2 domain specific search-shortcut features, but both take time to set up and then is not intuitive at all. Chrome just blows it out of the water.
Also wtf - if I type "hello" and press enter in the search bar in FF, it puts a "www." in front and ".com" at the end.. like holy hell, if I knew the domain I'll write .com myself, it really is no problem. I even went ahead and googled for 15 minutes and disabled this in some deep settings somewhere, but it still does it when I press enter too fast... damnit, it frustrates me every single day.
I hope they see this and fix this very-frustratingly-obvious anti-UX behaviour..
it's really jarring to be sent to a random domain when looking up something in a hurry.