One that can be easily read by 5-year-olds. Copywriters are very good at this.

Another, that are written like essays, such as this: http://www.wired.com/1996/12/ffglass/

How do you write like the latter? My first language is not English and I can easily write like the former, but not the latter. Even if I have a thesaurus by my side. I think there is something I'm missing