In his recent post “Go Faster By Not Working” Adrian talks about how having the entire team stop when the build breaks can result in the entire project going faster.
Lean manufacturing, the precursor to the “Agile” methodologies, has the concept of “Stop the Line”. When a defect in the product is identified, the entire assembly line stops to locate and rectify the factors that caused the defect.
The major difference in a software development “line” is that there is no physical assembly line, so it is easy to blur the distinction between what is and isn’t part of the product and hence the “line”.