The temptation to fill a slide with text is always there - people think if they spell their message out on their slides, then people will be sure to take in the information presented. But this is extremely counter-productive. People can listen to you, or they can read your slides. They can’t do both. As Garr Reynolds says, “If your slides can stand by themselves, why the heck are you up there in front of them?”
If your slides are designed to be PRESENTED, then you should only use KEYWORDS. If your slides are designed to be read, and not presented, then you are creating what Nancy Duarte refers to as SlideDocs. This is not what I am presenting about today, but by all means check out slidedocs.com
for more details.