NEW YORK — Retailers are rolling out online deals on so-called “Cyber Monday.” But now that shoppers are online all the time anyway, the 10-year-old shopping holiday is losing some of its luster.

Still, Monday is expected to be the biggest online shopping day ever, with estimates that it will rack up over $3 billion in sales.

“It’s no longer about one day, but a season of digital deals,” said Matthew Shay, president of retail trade group The National Retail Federation.

Online shopping is taking its toll on brick-and-mortar shopping. Frenzied crowds seemed to be a thing of the past on Black Friday — the busy shopping day after Thanksgiving — and sales fell to $10.4 billion this year, down from $11.6 billion in 2014, according to preliminary figures from research firm ShopperTrak.