News: Seven Best Add-Ons for IE7. No web browser is perfect, and no web browser does everything just the way everyone wants it to. Enter add-ons. Also called extensions or plug-ins, add-ons let third-party companies and users with programming skills extend the browser's functionality in different ways. They are your ticket to a customized web. Mozilla Firefox is known as the world's most extensible web browser, which is a big reason for its appeal among web geeks. But users of Microsoft's Internet Explorer 7, Windows Vista's native browser, need not be left out in the cold when it comes to add-ons. Here's our roundup of the seven best ways to trick out IE7. 1. ieSpellIt's a shame a spell-checker wasn't built into IE7, but ieSpell corrects that oversight. 2. 3. 4. 5. 6. 7. Save Images :: Firefox Add-ons. UnPlug :: Firefox Add-ons.