Whatever you may think about Edward Snowden, he did open our eyes to the level of Government monitoring and tracking capabilities. If you're not comfortable with the government reading all your text messages, or you just want to improve your overall security, secure messaging is for you.
When browsing the internet, many sites leave behind "cookies" on your computer. These can be used to remember your login the next time you visit the site, keep track of things you've looked at on various sites, and can be used to direct advertising to you. This is why when you search for something on the web, you see ads for that thing for the next week.