Microsoft tries to compete with its Windows Marketplace against the add-on dominance of Firefox. The main difference between add-ons that you find on the Marketplace and those that you find on the Mozilla website is that some Marketplace add-ons are not free.
This articles looks only at add-ons that are freely available on the marketplace website. I will mention Firefox add-ons that provide you with the same functionality if available as Firefox users may benefit from the listing as well because of it.
Most of the add-ons that can be downloaded from the Windows Marketplace for Internet Explorer are actually toolbars. I would estimate that about 50% of all add-ons are toolbars.
Note: Microsoft has removed the Windows Marketplace listings for the Internet Explorer add-ons. Most add-ons are no longer available. The new website over at IEGallery lists a couple of add-ons though that you may be interested in.
Additionally, Internet Explorer 7 is no longer supported by Microsoft.
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