The number of U.S. jobs posted online fell by 506,000 in January to almost 3.4 million, according to The Conference Board's measure of online help-wanted ads released today. For both January and December, online postings were down by more than 1 million.

"An expected increase in the unemployment numbers coming out at the end of this week, combined with this sharp January drop in labor demand, will widen the labor supply/demand gap," said Gad Levanon, senior economist at The Conference Board. "In December, the number of unemployed looking for work already exceeded the number of advertised vacancies by 7.3 million."