“PIVOT = A Change in STRATEGY without a change in VISION” Eric Ries
http://video.fastcompany.com/plugins/player.swf?v=fe3d427266cc5&p=fc_social
The Pivot is used for when your experiments stop producing results with your existing strategy but the vision remains solid. The above is an excellent video giving Eric Ries’ explanation of the pivot.
Found it over at fast company here.
Nick Hortovanyi's blog 
Nick,
Like the video, linked to it in a blog post over the weekend so that my few highly educated and discrminating readers have the opportunity to see it.
Cheers
Allen