Crowds were thin at U.S. stores and shopping malls in the early hours of Black Friday and on Thanksgiving evening as shoppers responded to early holiday discounts with caution and bad weather hurt turnout.

Some people on Friday morning said they had already shopped online or visited the mall the night before. That reflects the new normal of U.S. holiday shopping, where stores open up with deals on Thanksgiving Thursday itself, rather than waiting until Black Friday.

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While Black Friday seems to be losing some appeal in the United States, British shoppers have taken to the concept enthusiastically, with reports of large crowds at big stores and malls in the UK.

Shoppers in the United States spent more than $1 billion online, 22-percent more than last year, between midnight and 5 pm ET on Thursday, according to the Adobe Digital Index, which tracked 100 million visits to 4,500 U.S. retail sites.

As much as 20 percent of holiday shopping is expected to be done over the Thanksgiving weekend this year, analysts said. The four-day shopping burst will help set the tone for the rest of the season, signaling to retailers whether they need to drop prices or change promotions.

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The shopping season spanning November and December is crucial for many retailers because the two months can account for anywhere from 20 to 40 percent of their annual sales.