Text-based QA is practical to the extent that the types of questions being asked can be expected to have ready-made answers tucked away somewhere in the text corpora being accessed by the QA system. This has become much more feasible in this age of burgeoning internet content than a few decades ago, though questions still need to be straightforward, factual ones (e.g.,  “Who killed President Lincoln?”) rather than ones requiring inference (e.g.,  “In what century did Catherine the Great live?”, let alone  “Approximately how many 8-foot 2-by-4s do I need to build a 4-foot high, 15-foot long picket fence?”).