"A folksinger is someone who takes 5 minutes to introduce a 2 minute song"

Interesting quote, sian. I always take the trouble to explain the historical background to a song, (and say who wrote it if the author is known). Apart from hopefully making the song more interesting to the audience (I know I find it does, when I'm in the audience listening to someone else), it gives me something to do between songs while I work out what key it's in, adjust the capo, or change instruments, etc.

I like to know myself what a song is about, and what its historical context is, and I believe most audiences also get more out of it if they are told.

(Mind you, you can come unstuck. I once spent 5 minutes explaining a new song - new to me , that is - and forgot the words half way through the first verse. I had to abandon it and do another song instead. I felt a bit of a pillock at the time, but it was a good learning experience :-| )