• Black Friday kicked off earlier than ever this year.
  • Online sales on Wednesday hit $2.4 billion, a 31.8% increase from 2017. As of 5 p.m. on Thanksgiving Day, shoppers had spent another $1.75 billion online, up 28.6% from last year.
  • The explosive growth in online sales creates problems for some retailers, as companies including Walmart, GameStop, and Lululemon dealt with technical difficulties online on Thursday.

Black Friday now officially starts on the Wednesday before and in the wee hours of Thanksgiving morning. And, that’s not necessarily good news for retailers.

Shoppers spent $2.4 billion online on Wednesday, a whopping 31.8% increase from 2017, according to Adobe Analytics data.

By 10 a.m. Thursday morning, shoppers had spent another $406 million online. By 5 p.m., they’d spent $1.75 billion, representing 28.6% growth compared to last year.

The skyrocketing sales represent an increase in online shopping more generally, as well as a Black Friday sales “day” that is shifting earlier and earlier.

"Pre-Thanksgiving deals appear to have enticed consumers to spend a little earlier as we saw our second $2 billion day of the holiday shopping season," Taylor Schreiner, Adobe Digital Insights' director, said in a statement.

However, not every retailer was fully prepared for the increase in shopping on Thanksgiving Day and the day before.

The downside of success

black friday

Foto: Black Friday is going online.sourceKena Betancur/Getty Images

Shoppers on Walmart's website dealt with technical difficulties on Wednesday evening. GameStop shoppers complained about similar tech issues on social media. And, Lululemon's website crashed on Thursday, apparently buckling under traffic.

"We knew it would be a busy day, and I suppose technology got away from us this time around," Lululemon's account responded on Facebook. "I totally understand that this can be frustrating as someone trying to shop online, and know that we're doing everything we can to rectify the situation as soon as possible. "

According to Bob Buffone, chief technology officer at web optimization software company Yottaa, companies' problems were likely rooted in not having the infrastructure to handle the traffic.

"If you have not load tested your site at five times normal traffic volumes, your site will probably fail," Buffone told Business Insider on Thursday.

Not being properly prepared for Black Friday is even worse than having a site crash on any other shopping day.

"It's easy to go to a different site and spend their holiday money elsewhere," Buffone said. "Depending on how long the site is down, it can cost retailers a lot of money and also result in damage to the brand as shoppers take to social media to express their frustration."

In addition to technical issues, earlier shopping can mean deals selling out earlier. Doorbusters are, by nature, limited. But, earlier sales can also mean things selling out earlier - which can result in frustration for shoppers who are used to a more traditional Black Friday shopping schedule.