Update README

Closes #2984

README.md

@@ -2,8 +2,7 @@
 
 TextSecure is a messaging app for simple private communication with friends.
 
-TextSecure can use either data (WiFi/3G/4G) or SMS to communicate securely, and all TextSecure
-messages can also be encrypted locally on your device.
+TextSecure uses your phone's data connection (WiFi/3G/4G) to communicate securely, optionally supports plain SMS/MMS to function as a unified messenger, and can also encrypt the stored messages on your phone.
 
 Currently available on the Play store.