See, a while back, Google gave iGoogle a makeover that moved page tabs to left side of the screen--where they eat up a small but noticeable chunk of screen estate. (It's less problematic for users of widescreen monitors, but definitely an issue on netbooks, where screen space is at a premium.)
Unfortunately, there's no obvious way to go back to the old iGoogle interface, which had page tabs up top where they belong. (Well, actually, there is--keep reading to find out how.)
The iGoogle Tab Remover extension does exactly what it sounds like: It hides those tabs, thus giving you more space for your iGoogle gadgets. You can reveal your tab menus just by mousing over "iGoogle Tabs," and there's also a Firefox menu option to enable and disable the extension.
Of course, as one user points on the extension's Mozilla page, you can, in fact, revert to the old-style iGoogle interface via this URL: www.google.com/ig?gl=all. Who knew?
Either way, it's nice to have a choice.