I am using Adobe Premiere Elements 8. I have read up on the difference between a video's horizontal pixels and a picture's square pixels.
I am having a difficult time with creating a video with HD or very clear text. For example, when I view the following example video (not mine) on YouTube (http://www.youtube.com/watch?v=HEheh1BH34Q), I see that the user has the option of switching between 360p, 480p and 720p. When you select 720p from this example, you can see the text is extremely clear and can be compared to the clarity of a vector image in Adobe Illustrator.
I am trying to create a very simple test file in Adobe Premiere Elements 8 in which the text appears extremely crisp and clear (like a vector). For the text, I am using an Elements title or a Photoshop image (from Photoshop using horizontal pixels, i.e. File > New > Preset > Film & Video). In all cases, it appears nice and clean in Adobe Premiere Elements 8, but when I export/share a file, the file loses quality and text appears blurry. I have checked the output settings and am exporting in most test cases to an MPG.
You will get the clearest text if you create your titles in Premiere Elements rather than import them from another program.
Also, YouTube can be a challenge to get great quality on, since they're continually changing the way they re-encode videos after you post them. The fAQs to the right of this forum offer solutions for the best formats to load to the site.