The built in Google search that you can access from Firefox’s context menu by highlighting a word on a page is a basic search. But you must be aware that Google has plenty of advanced search operators that can help you filter search results. For example, intext:, intitle:, inurl: etc.
Advanced Dork is an addon for Firefox that enables you to search Google using these advanced search operators, directly from the context menu. Simply highlight the word you want to search, select Advanced Dork and choose from over 15 advanced Google operators.
Advanced Dork has some additional options that can be turned on in the Options menu. Right click anywhere on the page with no text selected to search the current page’s HTML title with the Google's “intitle” Operator, and the current page’s HTML ALT tags using the “allintext” Operator.
Again, right clicking on a link provides you more options under the Advanced Dork item. You are able to search the link using “site:”. “link:” and “cache:” operators. These operators are often useful for webmasters for SEO purposes. You can also access these operators by right-clicking on the address bar.
Vey useful addon if you frequently use advanced operators. Even if you have never used advanced operators, now you will.