Early discounts may have taken some of the shine off Cyber Monday, but the key online holiday shopping day is still expected to attract bargain hunters who may not have had their fill over the weekend.

Cyber Monday — a term coined five years ago for the day many people return to work after Thanksgiving and make online gift purchases on their computers — remains a prime shopping day online. But its novelty has now been partially eclipsed by e-commerce promotions earlier in the season, including on Thanksgiving itself.

Retailers from BestBuy.com to WalMart.com and Staples.com even opted to offer Cyber Monday deals one day early, on newly coined “Cyber Sunday.”

The key is versatility, online experts say, as well as making sure shoppers heading to the Web always find something to inspire them to click on a sale.

Marketing firms say tactics have changed in luring consumers to buy online. Whereas in prior years a full e-mail inbox of online deals awaited those back at work on Monday, the offers now increasingly come on Black Friday if not before.

U.S. online sales were up 33 percent on Thanksgiving this year, according to Web analytics firm IBM Coremetrics.

Online deals will continue throughout the holiday season. Amazon.com, the largest online retailer, said its Black Friday deals would last all week; Target.com and eBay have set up daily deals through December.