We asked the same 60 questions using DRS (digital reference services) in Japanese public libraries, face-to-face reference services and Q & A (question and answer) sites. It was found that: (1) The correct answer ratio of DRS is higher than that of Q & A sites; (2) DRS takes longer to provide answers as compared to Q & A sites; and (3) The correct answer ratio of face-to-face reference services in public libraries that provide (do not provide) DRS is higher than (the same as) that of Q & A sites. Considering that a majority of the Japanese public libraries do not provide DRS, the result indicates that Q & A sites and face-to-face reference services are comparable in terms of their ability to answer questions. However, the public libraries that earnestly provide DRS can outperform Q & A sites. (Contains 7 tables and 6 footnotes.)