The rejection of the Oral Torah produced practices markedly different from mainstream (Rabbanite) Judaism: Karaites keep no fire or lights through the Sabbath, count the festival of Shavuot differently, and diverge on marriage and purity law. The affirmation defines Karaism against the great current of rabbinic Judaism, which regards the Oral Torah as given at Sinai alongside the Written.
Once a substantial movement, Karaite communities survive today chiefly in Israel, preserving a scripturalist alternative within the Jewish world. The medieval conflict between the two camps produced substantial polemical literature; the Rabbanite scholar Saadia Gaon, head of the Sura academy in Babylonia in the tenth century, wrote influential refutations of Karaite positions that shaped Rabbanite self-definition as much as they attacked Karaism.
A distinct Karaite community developed among the Crimean and Lithuanian Karaites, who over centuries emphasised a Turkic ethnic identity distinct from rabbinic Jews; this self-differentiation had grave consequences during the Second World War, when Nazi racial authorities, after disputed internal debate, classified Crimean Karaites as not racially Jewish, so that most were spared the mass killing inflicted on Rabbanite Jewish communities in the same region, a history that remains sensitive and debated in Karaite and Jewish historiography today.