DuckDuckBang! is an unofficial Firefox add-on that adds touch-friendly buttons for quickly making !bang queries.
Typing !w is easy on a desktop, but cumbersome on touchscreens. With DuckDuckBang!, making a !bang query is as easy as tapping a button.
Currently the add-on provides buttons for searching Google, Wikipedia, and Youtube. Future versions of the add-on will allow users to select the buttons they want.