We've picked out four of that are also free of charge. You can search for and install all of them using the Addon Manager within Firefox (From Tools select Add-ons, then click the Get Add-ons button in the window that appears).
This handy plugin does just one thing. Once installed, it'll turn any currency amounts listed on a Web page into hyperlinks. When the links are clicked, a small floating window appears that can convert the amount to any other currency based on current exchange rates, with data from iforex.com.
In other words, if you're browsing a European site and are thinking of ordering a product, simply clicking the price in euros will allow you to instantly and accurately see what it is in U.S. dollars.
A silly irritation is that the add-on doesn't detect the currency, so you'll need to select it from a dropdown list in the pop-up window. However, the pop-up remembers what you selected last time, so if you frequently have to convert Euros to US dollars, for example, there'll be little hassle.
Described as the Facebook of the business world, with others in your profession. If you're a fan of the site then the official LinkedIn Companion for Firefox extension is a must.
The add-on does three main things. The first is to add a button beneath the bookmarks toolbar that displays a menu, showing shortcuts to various sections of the LinkedIn Web site. It also allows you to share the Web page you're browsing on your LinkedIn profile, and tracks recently-viewed profiles.
Secondly, the extension adds LinkedIn entries to the Firefox search box so you can quickly search both the LinkedIn site and also its jobs section.
Thirdly, and arguably most useful of all, the add-on places a small LinkedIn icon alongside the name of contacts within Web mail services, such as Gmail and Hotmail. Clicking this then shows a pop-up window with a short précis of their LinkedIn profile, if they have one. Clicking the link will display their whole profile and you can add them as a contact.
The only irritation with the add-on is that the browser interface button takes up a whole toolbar of its own, wasting screen space.
Despite its name, the gPDF is an add-on designed to allow the quick and easy viewing of office files within Firefox, including but not limited to PDFs. It's extremely simple to use: once installed, single-clicking any link within a Web page that points to a PDF, Word document (both .doc and .docx), Excel spreadsheet (.xls and .xlsx), or PowerPoint presentation (.ppt and .pptx) will open them in the Google Docs viewer. Clicking rich-text files (.rtf), comma-separated value spreadsheets (.csv) or OpenOffice.org files will open them in Zoho Viewer.
In both cases you don't need to have a Google Docs or Zoho Office account, or be logged into them.
Thanks to gPDF, for most office documents there's no longer any need to download and view them in the relevant program, which can take a lot of time.
You can still download files manually by right-clicking them and selecting Save As, although in both Google Docs and Zoho Viewer you can select to save-out the file after viewing using the menu options.
Describing itself as a ‘document harvester', OutWit Docs is a clever little plugin that transforms Google into an office document search engine. Just click the OutWit button next to the home icon on your browser toolbar and a separate search window will open. Entering a search term in the usual search field at the top right will search Google but only return Microsoft Office, OpenOffice.org, CSV or PDF files.
As such, OutWit Docs is an excellent business research tool. Double-clicking any file in the results will download and open it instantly, while you can "catch" documents for further investigation later by dragging them to the Catch box. By checking a box beneath the Catch box you can also cause the files to be downloaded automatically when they're caught.
Although it's not the prettiest add-on, OutWit Docs is first-rate for those who have to search online for business materials.