It's slightly different, but you can do almost the same thing with Keywords in the Firefox location bar, and they presumably could support the bang syntax (or whatever) as well.
By all means, try and replicate this complete list in your Chrome browser: https://duckduckgo.com/bang.html. I'll wait...
What makes the DDG !bang system awesome is its enormity. You don't look up what !bang to use to search something. You assume it exists, do it, and 99% of the time, you're right. That's a game changer.
I don't write Perl, but I know !cpan exists. I don't even have to look. I don't even know exactly what site it's going to search. But I know if I !cpan twitter, I'm going to be looking at a list of Perl libraries for tweeting.
That's the DDG killer feature. You want to do some kind of site-specific search or lookup, you just type in the most logical sounding !bang and assume it will work. You're simply never going to replicate that inside your browser.
> 3. Enormity has been in frequent and continuous use in the sense “immensity” since the 18th century: The enormity of the task was overwhelming. Some hold that enormousness is the correct word in that sense and that enormity can only mean “outrageousness” or “atrociousness”: The enormity of his offenses appalled the public.