The way I see it, long exposure is used:
1) in really low light situations when you need to keep the shutter open longer to let in as much light as possible. (Nothing to show for this one folks ’cause my camera had long been packed up by the time the sun went down tonight.)
2) to show movement in an image.
3) to create blur for some artistic purpose – intentional or not.
Something about the colours and the way they look almost feather-like on the contrasting white background made me keep this one. It’s my “it-didn’t-work-out-so-I’ll-call-it-artistic-shot”. Argonaut Rowing Club, Toronto. Exposure: 1/4 sec @ f/22