XKeyscore see your internet activities in real-time

The NSA can see you all, this is what the latest news leak said, NSA or "National Security Agency/Central Security Service Public Information" is able to track activities of anyone in the world in real-time, reports Edward Snowden's using a software named XKeyscore.

They only require email address and/or IP address to track your emails, browsing monitor your facebook activities including chat and message all that in real-time, all these massive huge data require a high-end extreme computing system, imagine 850 billion events and 150 billion Internet records, with more than 20 terabytes being added daily to the server, the NSA report back that they use the XKeyscore only against "terrorists" and criminals, but who trust these guys, and who know how they identifies people as "terrorists" !

XKeyscore central cores all over the world

Essentially, it’s armchair surveillance via WYSIWYG drag-and-drop menus. If we can believe what we’re hearing.
That “if” is rather crucial.
There are only two ways the NSA could amass such huge amounts of unencrypted data: by intercepting everything at the ISP level and decrypting in almost-real time any HTTPS or otherwise encrypted transmissions, or by having backdoors in dozens if not thousands of companies’ systems to access data on a regular and continuous basis.

"I, sitting at my desk," said Snowden, could "wiretap anyone, from you or your accountant, to a federal judge or even the president, if I had a personal email".
US officials vehemently denied this specific claim. Mike Rogers, the Republican chairman of the House intelligence committee, said of Snowden's assertion: "He's lying. It's impossible for him to do what he was saying he could do."

Some screenshots how the software work.