Databases are only as good as their underlying indexing technologies. At the user level, these are seen as keywords, topics, subjects, and high level categories. In the back room, the coding is about giving you the most relevant set (question/ answer, problem/solution, exercise sets) for your needs.
Needs vary, and so does ProblemEngine. Are you taking the SAT? Are you teaching string theory? Are you qualifying for Microsoft O/S, Cisco Network, Oracle database or IEEE circuit design certification? Do you need to pass the State of Delaware Polygraph Examiner certification exam? Do you need Mrs. Altmann's 2018 Geometry exam? Are you interviewing with Google for a Data Scientist position? Millions of these types of objectives and their needs are included in every type of search, from raw keyword, to questions and needs in the exact form above.
Many web services like Wolfram, Wiki, Google, Bing and others are working on "user friendly" question formats, but it is easier for us, because of our laser focus on prep and q/a, p/s, exercise pairs. Most of the advanced forms of these only result in vaguely related forums on today's searches, but with specialized databases, the "top 10" results can be direct answers to your exact questions.
This also is the future of Wikipedias, and the present of our own captive "relational" Wikis: How does A relate to B? "What is the difference between a remainder and a modulo?" or "What is the difference between a sequence and a series?" Just like Jeopardy, if you ask this on ProblemEngine, you'll get a question/answer, problem/solution, exercise response, and you can specify if you want a single answer set, a complete exam, at what level of difficulty, and in what format: written, audio, video, hinted, animated, illustrated, broadcast, or an entire cited bib, index, glossary and text.
AND: how FUN do you want it? Fast and dry? As a puzzle? Game? Smart phone or email text, app or answer? Graphic novel? Who says test or interview prep can't be fun? We're even working on VIRTUAL JOB INTERVIEWS with real interviewers using 3D RIFT technology.