Opera Browser, User Mode
A quick note for any usability concerned designers out there.
I thought I'd second the opinion -- I use Opera's "User Mode" feature frequently. When you have "Debug with Outline" turned on, it shows you the borders of all your block elements like table cells, divs, etc. It's handy when writing dynamic reports, to make sure you've dotted your Ps and crossed your Qs. Also, hitting the "G" key to turn off graphics is a quick way to check that you have ALT tags, etc.
This was always one of my fav features in Opera, especially for those "cool" sites, with the black background and the blue font - or whatever other "cool" combination you can imagine :)
Most of these features are available in Mozilla and kin with the Web Development bookmarklets. (google for em).
I wondered about whether Mozilla had these.
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