Bloomberg details (the below was pieced together from a broader article):
The quits rate can serve as a measure of workers’ willingness or ability to change jobs. The number of quits (not seasonally adjusted) in July 2011 increased from 12 months earlier for total nonfarm, total private, and government. In the regions, the number of quits rose in the Midwest and West.
The layoffs and discharges level (not seasonally adjusted) declined over the 12 months ending in July for total nonfarm and government. The number of layoffs and discharges was little changed in all four regions over the year.
So, in theory an increase in the number of quits relative to layoffs should reflect an improving economy and an improving economy should be reflected in the equity market. I was surprised by how strong this was reflected in the data (maybe just luck).
If one were to believe in this relationship, then one would notice how equities seem to lead out of recessions, but the ratio would have given investors a heads up that things were not right back as early as late 2006. I'd also note that the ratio has come back since the market bottom, but not nearly as much as the equity markets have.