There can be any number folk/traditional elements in a performance, a song, or a composition-it doesn't have to be all folkloric to count. A new pop song may use a very old and much used melody--A hip-hop tune can use a line or phrase from traditional ballads(and they often do)--The singer/songwriter may write his own words and melodies, but the subject may be traditional, a narrative about an unfaithful love, for instance--