XKeyscore allows analysts to “search with no prior authorization through vast databases containing emails, online chats and the browsing histories of millions of individuals” around the world according to a Guardian story published last summer. A document published by Der Spiegel describes an XKeyscore training at the NSA's European Cryptologic Center, revealing that analysts may also be rewarded for their exploration within the system with something called "Skilz points."
It's unclear from the report exactly how the Skilz points system works, but from these snippets it sounds pretty similar to the reward systems found in many video gaming platforms -- earning points and leveling up.
The NSA declined to comment specifically on Skilz points or the agency's use of gamification in response to a Washington Post inquiry. Instead, the agency shared a statement sent to Der Spiegel that defends XKeyscore as a tool with "stringent oversight and compliance mechanisms built in at several levels" and noted that President Obama had signed a directive in January affirming that all persons "regardless of nationality" have a privacy interest in their personal information that the U.S. will take into account when planning signals intelligence operations.
But based on the feedback detailed in the report, it seems like the Skilz points system was pretty successful at getting analysts to dig deeper into the agency's vast data troves.
The NSA is required by law to obtain an individualized Foreign Intelligence Surveillance warrant if targeting a U.S. person, although such restrictions do not apply when the NSA is snooping on communications between an American and a foreign target. However, the Guardian claimed that XKeyscore provided the technical capability, "if not legal authority," to target Americans without a warrant if the analyst had identifying information about them -- such as an e-mail or IP address. According to job postings, the tool seems to have been in use at least through last fall.