What makes me ask this question is this answer by @ezra to http://genealogy.stackexchange.com/questions/12159/spelling-of-surname-kowesnki-kowenski.
The answer claims the name "Kowenski" is Jewish, even though it is obviously Slavic; this is not surprising considering many Jews lived in eastern Germany, Poland and Russia for thousands of years, but still, the concept of "Jewish surname" surprised me. Is there such a thing? I was under the assumption that Ashkenazi Jews had Germans (mostly) or Slavic (more rarely) names.
My understanding is that Jewish religion is traditionally passed from mother to her children, while family names are traditionally passed from the father to his children. As such, there should not be things such as Jewish surnames, as since the early 1800s it is common for Jews and non-Jews to intermarry.
But the main reason why they would have German/Slavic surnames instead would be simply because the surnames were invented after the Jews arrived in those countries (Germany, Russia, Poland), and were somehow "surnamed" with the same system as non-Jews, even though they lived somehow separated from other people.
I heard that names ending in "-berg" and in "-stein" sounds "typical Jewish", although those are actually German words.
I was surprising that on Wikipedia at least 3 "famous" people of Jewish origin have the same (German) surname as I. (By "famous" I mean famous enough to have a Wikipedia article). I don't think it's uncommon for a German surname to be equally common between Ashkenazi Jews and non-Jews, but I'd just ask in order to be sure or have more detailed information on the matter.