content: Isn't it obvious?  Easier to memorize. Mind you, the best principle is to use a passphrase, imo. Even more so than XKCD's comic on password strength. "I like tacos." as an example, without the "s, but with the spaces & period. I realize that leaves a bit to be desired in terms of lack of special characters, but as mentioned in that XKCD comic, Length > all other factors in terms of password protection (at least in regards to brute forcing them).  Something random and arbitrary (like "I like tacos." makes it hard to just guess too (as opposed to a birthdate, family name, wtv).