From MozillaZine Knowledge Base
Google Toolbar is no longer supported in Firefox 5 or newer versions. You can check out the features of the Google Toolbar using the interactive display of the toolbar on Google's site. This article examines what was in the Google Toolbar that Firefox users might have been using and suggests alternatives.
Note: Google Chrome does not have or use the Google Toolbar because, like Firefox, the features are built-in or accessible from the browser by other means such as extensions. Firefox has another powerful tool and that is keyworded bookmarklets.
- The Google Toolbar will not be updated for Firefox 5 or later Firefox versions.  Google finally decided that their problematic extension is beyond repair for the little benefit added for Firefox users. Google as with other browsers is eliminating or making toolbars less accessible.
- Google published a list of Google Toolbar extensions and Firefox extensions and features that can be used instead of the Google Toolbar see Toolbar not available for Firefox 5 or newer versions : Install or uninstall - Toolbar Help. We can start with that list and as Firefox users we can add more specific information rather than generalized searches.
- Google's list mainly involves extensions, but Firefox users can make much better use of Bookmarklets than Google or any other browser today, because of shortcuts. But keyword shortcuts and particularly their names are a personal thing so each person will choose their own keyword name -- even for the same bookmarklet. There are those who will not even learn some rudimentary keyboard shortcuts let alone many of those keyboard shortcuts that are actually available. Customizing existing keyboard shortcuts by (rebinding your keys) can be done with the "keyconfig" extension. For users who don't want to think of keyword shortcuts they can add bookmarks to the bookmarks toolbar to use like buttons.
- There are many Firefox extensions that have the same names as the Google Toolbar features because they are or refer to Google features that can be invoked by browsers: GBookmarks, Sidewiki (see below)
- There are so many Firefox extensions to choose from so that if you lose use of one, you can often find a similar substitute.
- Firefox -- Release Dates projected version release dates, these dates are of interest to those who need to know when updates are pending, which should be everyone.
- Dictionary (kws), a great many dictionary bookmarks are available, it is a matter of choice as to what dictionary/dictionaries to use.
- RSS feeds are supported in all browsers.
- Thesaurus (kws), a great many bookmarks are available mainly a matter of which thesaurus to use.
Google Toolbar features
Starting from a list supplied by Google. 
- AutoFill: See available add-ons to fill out forms. [fill web forms]
Basically AutoFill is built-in to Firefox, but extensions may add additional features, such as pass-wording the saved data; otherwise, make sure you do not discard saved form data (Tools > Options > Privacy > Settings).
- Find in page: Use the built-in feature in Firefox by pressing Ctrl-F (in Windows and Linux) or Command-F (on Mac).
- Highlight Search terms:
- "ColorResults" (11.3 KB) extension, highlight Google search terms Google as long as the user is scrolling the page
- "GoogleEnhancer" (22.5kb) extension, many optional features, auto next page, highlighting search terms, etc.
- Navigation bookmarklets (More examples of bookmarklets below)
- up: Up one Directory Level 
- Page sharing: Consider using other add-ons for sharing [share web page].
- [AddThis] (280.6 KB) to make sharing and bookmarking simple. Have all your favorite web 2.0 social networking, bookmarking, blogging, and e-mail services at your fingertips. Share any page, anytime, with anyone. Share interesting things you find on the web. 
- "Sidebar Companion for Google Sidewiki" (14.3 KB) extension, comments about web pages
- Create a keyword search for any site from its own search form: this is builtin to Firefox, right-click within the search form and choose "Add a Keyword for this Search..."; for others you might want to
- Create search engine: and that can be done with the "Add to Search Bar" (25.6 KB) extension with a right-click and choosing "Add to search Bar...".
- Search: using keyword shortcuts
- Search: more searches using keyword shortcuts
- Shorten link references: be aware that many people would rather have the actual link than use another website to to get to the page they want to go to.
- Spell-check: Use built-in spell-check in Firefox.
- Firefox has a builtin spelling checker, for some it works instantly, others have to create a persdict.dat file in their profile -- Spell checking - MozillaZine Knowledge Base.
Additional tips and information in these two links because you can do a lot more with the spelling checker than just check multi-row text boxes: Spell Check, and Spell Check Jumpstart
- After the Deadline - Spell and Grammar Checker (86.0 KB), an intelligent grammar, style, and spell checker, works with most web sites. When the ABC icon added to the lower-right corner of an editable area is green Firefox spell checking is used. When the ABC icon is toggled to red the extension's proof reading occur (red underscores for spelling or misused words, blue for style, and green for grammatical errors) -- right-click on word(s) to see type of error or suggestions under the "After the Deadline" logo and click on "Explain..." for additional information. [Options]. Warning: since it is used within web pages as an editor, it will destroy HTML and & symbols in Wiki documents some of which is used within urls.
- Translate, Translation, Page translation: See available add-ons [language translate].
Use of keyword bookmarklets is all that is really necessary:
- tr: translate current page to English (Google translate) (See additional details below)
- tr:s Translate selected text: (Google translate)
(See details below)
- tr:text translate text to English (Google translate)
(See details below)
- When you see an extension that is 1KB (compressed download size) there is a good chance, you could use a simpler bookmarklet instead. There are also a number of great extensions that are simply collections of bookmarklets converted to an extension with a user interface added.
- Translations with an extension, for ease of use particularly with a context menu for a selection
- gTranslate (33.8 KB), make a selection then right-click to bring up context menu.
- Google Dictionary and Google Translate (18.4 KB), in-line dictionary for any word you point to or double-click; whole page translation of any web page in another language.
Create a bookmark as follows. It will translate to whatever language you have set for yourself (English).
Name: tr: translate from fr, de, etc.
Description: translate from (fr, de, etc.). Test page http://web.de/ and http://web.nl/
After creating the bookmark, right-click on the bookmark and fill in the keyword
To invoke simply type tr: into the Location Bar.
Name: tr:s translate selected text to English (Google translate)
Description: translate from (fr, de, etc.)
To invoke simply make a selection then type tr:s into the Location Bar, and press "Enter"
Name: tr:text translate text to English (Google translate)
Description: translate from (fr, de, es, etc.)
Bad examples for these: (Good Morning. Have [a] nice day.)
tr:text Guten Morgen. Haben schönen Tag.
tr:text Bonne matin. Avez belle journée.
tr:text Buenos días. Tenga un buen día.
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