Small and medium-sized online retailers enjoyed big sales gains over the Thanksgiving holiday shopping weekend.

In categories such as art, sporting goods, apparel, skincare and fragrance, smaller e-retailers had growth rates in high double digits. For example, David Sasson, president and CEO of online-only art retailer OverstockArt.com, No. 825 in the Internet Retailer 2017 U.S. Top 1000, says sales were up 96% year over year during the holiday weekend stretching from Thanksgiving through Cyber Monday.

Broadly, it was a record-breaking weekend. Shoppers in the U.S. spent a record $6.59 billion online on Cyber Monday, up 16.8% from $5.65 billion last year, which made the day the biggest U.S. online sales day. (Numbers are rounded.) Of that $6.59 billion, shoppers spent $2.00 billion on mobile devices ($1.4 billion on smartphones and $600 million on tablets), up 30.7% from $1.53 billion on Cyber Monday 2016. Black Friday online sales also hit a new high, topping out at $5.03 billion.

Sasson says several factors contributed to OverstockArt.com’s gains during the five-day holiday period, including upgrading its site so that it loads faster and is easier for shoppers to find the products they’re looking for. These changes went into effect throughout October and into November.

“Our main focus was on improving conversion and customer experience,” he says, adding that the retailer improved the quality of the product images that a shopper sees once she clicks on an image to enlarge it so that she is able to see the products in greater detail.

Throughout the past year, Sasson says the retailer optimized its Google AdWords account to enable a better return on its search marketing spend. Sasson declined to specify what kinds of changes the retailer made, other than to say the retailer spent time “continuously improving (its site) content and giving Google a reason to find it.” Sales resulting from organic searches that started on Google were up nearly 90% year over year for the five-day holiday weekend while traffic from Google searches was up by 36% year over year.

“A lot of it is Google Shopping,” he says. “Google Shopping has been really, really big this year. Especially if you’re searching for a painting by name, meaning relatively high intent, you’re now seeing the results of that painting framed on Google Shopping. You go from there and you’re now seeing this is how much I can pay for it and where I can buy it. This is something we used to have fairly poor results on, so this is a big change for us.”

Heading into the 2017 holiday season, Sasson says OverstockArt.com analyzed its inventory and changed prices on products that weren’t selling as well to make them were more attractive to shoppers. For example, the retailer pre-framed prints that weren’t selling well and promoted them for $99, which is an 80% discount over what it would cost a shopper to buy the art and frame separately. While the lower prices may have led to selling the products for lower-than-usual profits or even a loss, Sasson says it’s better than having them languish on the retailer’s shelves.

While Sasson is happy with Thanksgiving weekend results, he says there’s no time to dwell on the success, even if it was a 96% year-over-year sales gain.

“[You have to] engage your team and make sure everyone understands that you have to hit the iron when it’s hot,” he says. “It starts with your [online] storefront and making sure there are promotions and inviting themes and that you come up with new ideas, new promotions.”

Online fashion marketplace Spring experienced a major spike in mobile traffic and mobile sales on Black Friday, the day after Thanksgiving. Spring reports total sales jumped 88% year over year, with mobile sales up 91% and desktop sales up 87%.

Athletic apparel retailer Left Lane Sports reports that mobile accounted for 58% of all traffic to its website from Thanksgiving through Cyber Monday, up from 46.5% during the same period last year. Left Lane’s mobile conversion rate increased by 52.8% during that stretch.

Skincare brand Vanity Planet reports that its online sales grew 45.2% year over year from Black Friday through Cyber Monday to $617,000, up from $425,000 last year. Mike Ponzillo, co-founder of Vanity Planet parent company Dastmalchi, says that $617,000 beat his projection of $500,000 for the weekend by 23.4%.

Ponzillo attributes sales gains, in part, to Vanity Planet’s work with social media influencers. The online-only retailer sent boxes of products to influencers and asked them to Instagram a story about their experience.

Meanwhile, Jason Apfel, president of online-only perfume and beauty products retailer FragranceNet.com Inc. (No. 183) reports that Cyber Monday was the biggest sales day in the retailer’s 20-year history.

Sales exceeded $3 million in a single day for the first time, and FrangranceNet.com sold nearly 90,000 bottles of perfume—more than a bottle per second—on Cyber Monday. Mobile drove a large portion of sales Monday, with 41% of orders placed on mobile devices and 58% of traffic coming from mobile devices. Last year, those percentages were 33% and 48%, respectively.

Enhancements to the retailer’s proprietary bidding software helped it make better decisions on how to use its search marketing budget. “Our tool automatically adjusts bids at certain click intervals based on numerous factors, [including] average position, ROI, inventory levels, competition and impression share,” Apfel says.