In light of Edward Snowden exposing secret government surveillance activities, and exploits such as the Heartbleed bug, people are becoming more aware than ever that what they write in emails may be read by government agencies, both local and foreign.
The most recent revelation of digital eavesdropping came last week, when Vodafone, an International mobile phone and data provider, revealed that, in six countries that they operate, law enforcement and government officials can tap into their network without any type of search warrant (http://www.bloomberg.com/news/2014-06-07/vodafone-prompts-protests-over-government-wiretapping.html).
In light of these privacy infractions, Google has announced testing of a super-secure email service that will provide end-to-end encryption (http://googleonlinesecurity.blogspot.ca).
According to the New York Times, Google is also taking steps to secure their entire digital infrastructure from prying eyes, be they the U.S. National Security Agency or some foreign intelligence unit (http://mobile.nytimes.com/2014/06/07/technology/internet-giants-erect-barriers-to-spy-agencies.html?emc=edit_tnt_20140606&nlid=59884265&tntemail0=y&_r=0&referrer=).
While these developments certainly provide a measure of comfort, data security really begins at your keyboard. If you only want your email attachments to be read by the intended recipient, make sure you encrypt them.