If you have not replaced Internet Explorer (IE) with Firefox, you are really leaving yourself open to security threats plus missing out on an improved browsing experience. In addition to not supporting ActiveX, which will solve most of your security concerns, Firefox offers hundreds of extensions to improve your security and enhance your browsing experience.
Another great extension is SiteAdvisor, which is now owned by McAfee. Site Advisor displays a green, yellow, or red indicator on search results, as well as on the bottom of my browser window to indicate their rating of the site. In most cases, I wont follow any red, and only if really important will I click on a yellow designated link. I can even easily visit the SiteAdvisor site before I follow the link, so I can learn why the site was given the particular rating. For example, recently I was doing some research, but a promising site had a red rating. What I learned was the site I wanted to visit linked to one unsafe site. So, I visited the site I wanted, but was sure I never followed a link from their to the real unsafe site. Note that I believe SiteAdvisor is also available for IE, though I have not tested it.
Other useful extensions include links for posting to Digg and Del.icio.us – these are social voting and bookmark sites that are quite informative and fun. I have also included the Google toolbar so I can take advantage of their anti-phishing tool. Of course Firefox includes Google search as a default feature, but now I can change that default to my second favorite search engine, so now I have easy access to two search engines.
For more information on extensions available for Firefox, try reading the following articles. Information Week published 5 Tools to Bullet Proofing Firefox on July 14th. The article discusses some of the extensions I already covered, including SiteAdvisor and NoScript, as well as some additional information. Leslie Franke has an extensive site covering Firefox (54 entries as of this time), including a great article about Firefox extensions, Mozilla Firefox – Have It Your Way! So if you don’t believe me, learn from Leslie and switch to Firefox.
July 29th -- I found another good resource that reviews some Firefox extensions: 13 Great Firefox Extensions for Web Professionals from Adam McFarland. If you do any sort of web work, Adam reviews some extensions that can be of benefit to you.