If you aren't familiar, ClearType is a little known display effect in Windows that smooths fonts. If you're on a Windows XP machine, you can easily test this out:
Here's a quick visual for the reading impaired:
If it's working, you'll see that your text is smoother and, perhaps, easier to read. Of course, being a web designer I can't actually use this because I have to take into account that most users do NOT have this turned on. I wonder why?
Because a standard cathode-ray tube (CRT) screen uses an electron beam to excite pixels, and does not have specific pixels at a specific location, you do not experience the same benefits that you experience on an LCD screen when you use a CRT screen. However, because ClearType still includes antialiasing support, you may see some improvement when you enable ClearType on a CRT screen.
Huh. Strikes me as lazy because there's this nifty tool out there called ClearTweak that allows you to tune the contrast and "fuzziness" of the smoothing. It seems to solve the problem on both my LCD and CRT screens. I guess when XP was being rolled out this was a low priority and they needed an excuse to leave it unfinished. My guess is that in the next generation of Windows they'll have this all figured out.
Please give a show of hands if you're already using ClearType.