Introduction

If you're not already aware, YouTube doesn't exactly have "great" quality video.  If you're uploading text, or a movie from the desktop it can be even more obvious that quality isn't high on the list of YouTubes priorities.

So, what to do?

1. Capture at 1200x720 instead of the default YouTube size.  We'll likely up the preset size in iShowU soon, or add an HD version specifically for YouTube.
2. Don't have high degrees of scaling. That is: Don't record full screen to 640x480.  The scaling itself reduces quality. Putting the scaled result through YouTube doesn't help matters.  Try to record at close to 1:1.  So if you're capturing 1200x720 make youre capture area that size as well for best result.   1200x720 should be OK if you're recording a laptop screen (full screen 1440x900) but "ok" can be subjective.
3. Use an alternative service.  Blip.TV provide higher quality and also lets the viewer see the original (uncompressed) video source.