Americans jumped on deals and promotions offered online on Cyber Monday, spending $1 billion and making it the busiest online shopping day ever, according to new data.

Research firm comScore Inc. says revenue rose 16 percent from a year ago to $1.03 billion on the Monday after Thanksgiving. Since the beginning of November, online sales are up 13 percent to $13.55 billion.

The improvement is welcome for retailers hoping that Americans start spending more freely. But shoppers are still holding out for bargains and spending cautiously as unemployment remains high.

According to ShopperTrak figures, revenue at brick-and-mortar stores was flat over the weekend following Thanksgiving, but traffic rose 2.8 percent.

A clearer picture of spending will come Thursday when the nation’s retailers release revenue figures for November.