In the age of page zoom being the default way browsers allow users to increase the size of content on a webpage (standard on most browsers for a while, and on IE since version 7), it can be easy to lump in users who resize text with those using IE6, and unwittingly subject the former to your disregard for IE6.In case you needed a reminder that this is a bad idea, consider a scenario I was unaware of until recently. On Windows (and presumably with other operating systems, though a quick glance at the Universal Access panel on my mac suggests that zoom is, again, the default and perhaps only possible behaviour), users can increase the default size of the system fonts from the “normal” settings of 96 DPI to the “large” setting of 120 DPI (and also, seemingly, other custom values). This seems to be roughly equivalent to twice increasing the font size via Firefox’s ‘Zoom Text Only’ option.
While Firefox ignores this OS-level increase, and will leave the font settings you, as a web developer, have so carefully crafted, IE7 (and later versions? I wasn’t able to test this) maintains the increased font size, wreaking havoc on your layout if you’ve been cavalier enough to count on users zooming rather than resizing.