There is also another category of folk song, that is constantly revitalised, adapted and updated, and so can withstand the passage of time; I refer to the type of song where each (short) verse is self-contained, a little like some shanties, and allows the participants to make up their own verses to add to it. These new verses are usually topical, don't last long in folk memory themselves, yet the skeleton-song remains.

I know of such songs in the Cretan ("mantinada") tradition, and I am sure I have heard similar in the English and Irish traditions; they would be typically tavern-songs or used in celebration at a wedding or even at a wake; each freshly made-up verse extolling the virtues of the person or event celebrated.