[Discuss] Most common (or Most important) privacy leaks

[Edward Ned Harvey (blu)]

All the talk about solving the password problem is interesting - but not related to the original question - 

What is the most common, or most important, area that you actually see people communicating insecurely, that should be secured?  Email has got to be #1, and I'm guessing Dropbox/Box/Google Drive #2.  Is that it?  Or is there more?