The Edward Snowden 'snowball effect' continues -- and it may affect your inbox, depending on who you are.

The Washington Post reports that the National Security Agency is collecting hundreds of millions of contact lists from personal e-mail and instant messaging accounts around the world, many of them belonging to Americans.

The report was based on top-secret documents provided by the former National Security Agency contractor, Edward Snowden, and confirmed by senior intelligence officials, according to the newspaper.

Snowden, the former NSA systems analyst, who fled the U.S. and now resides in Russia, continues to leave his footprints on the leaked information trail yet again.

Where does the spy agency target exactly?

"The NSA intercepts hundreds of thousands of email address books every day from private accounts on Yahoo, Gmail, Facebook and Hotmail that move though global data links," The Associated Press adds. "The NSA also collects about a half million buddy lists from live chat services and email accounts."

While the NSA doesn't deny the report, it explained the end goal in obtaining this information, which is to essentially protect Americans in the long run.

"The National Security Agency is focused on discovering and developing intelligence about valid foreign intelligence targets like terrorists, human traffickers and drug smugglers," the NSA said in statement released on Monday night.

"We are not interested in personal information about ordinary Americans. Moreover, we operate in accordance with rules approved by either the Attorney General or the Foreign Intelligence Surveillance Court, as appropriate, designed to minimize the acquisition, use, and dissemination of any such information."

Instead of targeting individual users, the NSA gathers contact lists in larger quantities "that amount to a sizable fraction of the world's e-mail and instant messaging accounts. Analysis of that data enables the agency to search for hidden connections and to map relationships within a much smaller universe of foreign intelligence targets."

How much data is collected on a 'typical' day?

According to an internal NSA PowerPoint presentation, during a single day last year, the NSA's Special Source Operations branch collected:

444,743 e-mail address books from Yahoo

105,068 from Hotmail

82,857 from Facebook

33,697 from Gmail

22,881 from unspecified other providers

On a grander scale, these figures (otherwise known as "typical daily intake") amount to a rate of more than 250 million a year, the Post reports.

The data collection doesn't take place on U.S. soil, instead it "depends on secret arrangements with foreign telecommunications companies or allied intelligence service in control of facilities that direct traffic along the Internet's main data routes." At the same time, the data collection includes "millions or tens of millions" of Americans, according to two senior U.S. intelligence officials.

While this colossal collection of information would be illegal if it were obtained in the U.S., the NSA has bypassed this legal obstacle by intercepting contact lists from points "all over the world," an anonymous official tells the Post.

The NSA's director, Gen. Keith B. Alexander, has defended "bulk" collection as an essential counterterrorism and foreign intelligence tool, saying, "You need the haystack to find the needle."