Here are some Internet Explorer 7 add-ons that mimic some useful features from Firefox that aren’t available in Microsoft’s browser (and sometimes add more features).
Inline search – search the current page as you type. It only works with Ctrl+F.
ieSpell – spell checker. Unlike the spell checker from Firefox, you need to press a button before seeing the misspellings.
IE7Pro – adds many features available in popular Firefox extensions. You get crash recovery, ads filter (with a dumb predefined list), mouse gestures, an option to change the user agent plus some tweaks like moving the menu on top and removing the search box.
Feed Folder – similar to the Live Bookmarks from Firefox.
Developer toolbar – explore the DOM of a web page, locate and outline some elements in a page.