The number of U.S. jobs posted online fell 7.9% month-over-month in July to almost 3.9 million, according to The Conference Board's measure of online help-wanted ads. Compared to July 2007, the number of online ads was down 5.4%.

"July is typically a slow month in terms of labor demand, but this month advertised vacancies were weaker than we would expect," said Gad Levanon, senior economist at The Conference Board. "There is little evidence of any approaching turning point in labor demand."