Online retailers had a decent Black Friday, with sales up over 8% from a year ago, and nearly 47% of online traffic coming from mobile devices throughout the day. Mobile played a big role this year in terms of both traffic and sales, and yesterday was especially notable for being the first Thanksgiving Day where mobile traffic to online retailers accounted for more than half of all online traffic. Today, those figures dropped a bit, however.

By 6 PM EST on Black Friday here in the U.S., mobile traffic had accounted for 46.7% of all online traffic – an increase of 24.2% year-over-year, but a drop from the 52.11% it claimed on the Thanksgiving holiday, according to IBM’s Benchmark data.

The holiday shopping season certainly started earlier this year, with a number of retailers online and off running discounted sales beginning on Thanksgiving Day. Amazon, for example, started running deals on its site mid-day, and that choice seemed to work out well for the retailer. As ChannelAdvisor noted in a separate report, its roughly 2,700 online retailers saw 20.1% year-over-year growth on Thanksgiving, but Amazon, search and other third-party marketplaces (meaning those not eBay or Amazon) saw the most growth over last year, as eBay lagged.

Amazon was up 25.9% year-over-year, outpacing e-commerce as a whole, but eBay grew just 3.0% over Thanksgiving Day 2013.

Mobile this year also played a part in crashing Best Buy’s website. According to web performance monitoring company Catchpoint Systems, Best Buy had three outages since Thanksgiving. The first outage was 5:00 AM to 6: 30 AM ET and the second was 8:00-9:30 AM ET, both on Thursday. On Black Friday, the site crashed again at 10 AM ET.

Meanwhile, despite retailers running early Thursday sales, Black Friday still proved to the be the bigger online shopping day. By 5:20 PM EST today, Black Friday online sales eclipsed those that took place on Thanksgiving, says IBM in its report released this evening.

Online sales were up 8.5% over the same period on Black Friday 2013, it found. Though mobile didn’t claim over half of online traffic as it did on Thursday, its percentage of the online sales is steadily increasing. This Black Friday, mobile sales accounted for 26.1% of all online sales, an increase of 24.7% year-over-year.

That being said, not all mobile visitors are the same when it comes to conversions. Consumers visiting from smartphones tend to browse, while tablet shoppers actually buy. On Black Friday, smartphones drove 33.6% of total online traffic, or more than double that of tablets (12.8%). But tablets accounted for 14.3% of online sales, versus smartphones’ 11.7%.

Also continuing yesterday’s trends, iOS shoppers remained more valuable to retailers with an average order size of $127.34 – higher than Android, at $101.82. iOS also sent more traffic than Android with 31.8% of all online traffic versus 14.5% on Android.

And finally, Apple iOS sales accounted for 20.2% of total online sales, nearly four times that of Android, which drove only 5.6% of all online sales.

Update: IBM’s early data appears to be an outlier this year. Other industry reports show a 20% increase year-over-year for Black Friday. IBM says its insights are drawn via the company’s $3.5 billion investments in commerce and customer engagement solutions, plus its expertise gained from work with 8,000 global brands and 35,000 client commerce engagements.