Automating repetitive Firefox tasks is one way to save your fingers from undue stress. From a sidebar you can toggle on and off, you can run, record, and edit macros. Recording is as simple as pressing a button before starting and clicking another to stop. For more advanced tasks you can turn to a set of intimidating demos, but frankly, we found the Web site wiki and step-by-step tutorials far easier to follow.
While iMacros can theoretically be used to input passwords, we strongly recommend encrypting them and either saving your master password to Firefox or inputting it each time. Being able to save macros as bookmarks and being able to share them via e-mail and Delicious are great features, though we wish we could schedule the macros, including running one or to just after booting Firefox. We also wish we could run macros in the background while we worked on other browser tabs. It's a modest request, but without it, just plan to take a break whenever a lengthier macro runs.
iMacros was designed to automate the most repetitious tasks on the web. If there's an activity you have to do repeatedly, just record it in iMacros. The next time you need to do it, the entire macro will run at the click of a button. With iMacros, you can quickly and easily fill out web forms, remember passwords, create a webmail notifier, download information from other sites, scrape the Web. You can keep the macros on your computer for your own use, or share them with others by embedding them on your homepage, blog, company Intranet or any social bookmarking service.