I like email because it's platform agnostic, produces a "igotacopy-yougotacopy" paper trail that's proven really hard to eliminate by people smarter than I.
Other people like SMS because their contacts are much more limited compared to email, there's no subject-line, and they think it's transitory. It's not, according to;
- The NSA.
- Your cell service provider.
- Me. Because I've mastered the screenshot function...