Black Friday, the official kickoff to the holiday shopping season, saw more foot traffic than ever before, according to estimates. But it appears so-called "doorbuster" deals offered the day before dinged sales.

According to ShopperTrak, which tracks retail foot traffic, there were more than 307 million store visits on Friday, up 3.5 percent. But Black Friday shoppers spent an estimated $11.2 billion, down 1.8 percent over 2011, when consumers spent $11.4 billion.

And for once, the sluggish economy is not to blame.

"It is all Black Thursday's fault," ZeroHedge.com said.

[Slideshow: Black Friday madness]

Shopping malls were "less hectic" on Black Friday this year, Bloomberg.com reported, as retailers "have turned Black Friday, once a one-day event after Thanksgiving, into a week's worth of deals and discounts."

And Thursday's deals "attracted some of the spending that's usually meant for Friday," ShopperTrak said.

Big box stores like Wal-Mart and Target were open on Thanksgiving night, drawing crowds that were--in some cases--rowdy. (Thankfully, it was nothing like the dystopian version of shopping hell recently envisioned by "Saturday Night Live.")

Another reason for the Black Friday dip: people skipped lines and shopped online. According to comScore, Black Friday online sales topped $1 billion for the first time, jumping 26 percent to $1.04 billion, compared to $816 million last year.

And according to IBM Benchmark, online sales rose 17 percent on Thanksgiving and 21 percent on Black Friday.