For quickly searching on a specific site (e.g price comparison portal, search engine, ...) defining search keywords/prefixes for the sites would be nice to have.

For example for searching in google user can define a searchprefix for example "g". When typing "g how is the weather in vienna" will search in google. Same with "b how is the weather in vienna" will search in bing (of course when "b" was defined before as search prefix vor bing).
Firefox has that feature where you can define search keywords for any website by calling the website, focusing on the search input textfield, clicking right mouse and set a keyword for the website.
Would be fine if this will be implemented on Opera for Android.

Regards