Also, it's a bad design decision to make bangs belong to search engines. In the past the firefox extension lookpick[1] solved that problem very well: They crowdsourced search engnines, had their own search box in the right corner of the screen, and to make it easy to pick the right search engines, search engines used searchable tags.
On top of that, if you add easy help for search operators for each site(also crowd sourced), would be really useful.
I wish there was something like that for chrome.
[1]https://addons.mozilla.org/en-US/firefox/addon/lookpick-sear...
