The NYSE A/D Line Refresher:

According to Stockcharts.com – the Advance / Decline Line (AD line) is one of the most widely used indicators to measure the breadth of a stock market advance or decline. The AD line tracks the net difference between advancing and declining issues. It is usually compared to a market average where divergence from that average would be an early indication of a possible trend reversal

They say a picture is worth a thousand words so I will let my chart do the taking. The upper plot is the S&P500 and the lower plot is the NYSE A/D line which is just now breaking up and out of a large ascending triangle to confirm the new highs on the S&P500. Ignore the doom and gloom crowd for now.