Thanks for that link ("What's a melody for?). The first couple of paragraphs of that more or less sum it up. The examples she gives (Lou Reed and Bob Dylan) are, she's right, four-or-five-note melody writers.

The thing is, though, that both Reed and Dylan were startlingly charismatic performers and off-the-wall lyricists, with tons more *attitude* than Ms Vega. Reed got his from the Stones/60s counterculture while Bob Dylan got his from the blues. I have no idea where Suzanne Vega got hers from, or indeed whether she ever actually got any.