Here's the extract. The article is entitled Das frühe Christentum und die Bildung (roughly translated Early Christianity and Culture):
Early Christianity is often regarded as an entirely lower-class phenomenon, and thus characterised by a low educational and cultural level. This view is false for several reasons. (1) When dealing with the ancient world, inferences cannot be made from the social class to which one belongs to one's educational and cultural level. (2) We may confidently state that in the early Christian urban congregations more than 50 per cent of the members could read and write at an acceptable level. (3) Socialisation within the early congregations occurred mainly through education and literature. No religious figure before (or after) Jesus Christ became so quickly and comprehensively the subject of written texts! (4) The early Christians emerged as a creative and thoughtful literary movement. They read the Old Testament in a new context, they created new literary genres (gospels) and reformed existing genres (the Pauline letters, miracle stories, parables). (5) From the very beginning, the amazing literary production of early Christianity was based on a historic strategy that both made history and wrote history. (6) Moreover, early Christians were largely bilingual, and able to accept sophisticated texts, read them with understanding, and pass them along to others. (7) Even in its early stages, those who joined the new Christian movement entered an educated world of language and thought. (8) We should thus presuppose a relatively high intellectual level in the early Christian congregations, for a comparison with Greco-Roman religion, local cults, the mystery religions, and the Caesar cult indicates that early Christianity was a religion with a very high literary production that included critical reflection and refraction.<idle musing>
Wow! Fifty percent literacy?! Most scholars think that literacy was under 10%, and closer to 2–3% (at best) if you want anything more than a bare functional literacy the equivalent of being able to read street signs.
I can't wait to see the responses. And maybe even grab the article itself, although my German is so bad right now that it would be a painful process to read it...