Marks & Spencer has taken a mobile-first approach to its Christmas ad campaign, upping digital spend to 25% for the first time ahead of what marketing boss Patrick Bousquet-Chavanne predicts will be the "biggest online Christmas ever". 'The art of Christmas' campaign, created by RKCR/Y&R, is a continuation of the retailer's recently launched 'The art of' concept. The ad, which is celebrity-free for the second year, shows an 8-year-old girl's journey as she travels through the different stages of Christmas.

"The Economist" wants to go from selling ads based on time to actually creating branded content using attention-based metrics, but its peers aren't sure it's the digital publishing metric of the future. The publisher has joined the likes of the "Financial Times" and "The Wall Street Journal" in measuring not just whether an ad is seen or not but for how long. What makes "The Economist"'s "Attention Buy" foray different is that it's the first to offer advertisers the opportunity to buy those slices of attention in-app and online.

Mobile payments company Square, headed by Twitter chief executive Jack Dorsey, has seen its value drop by almost $2bn in a year as it updated the market on its upcoming flotation. The company, which will be valued at $4.2bn in its initial public offering, will price its shares at between $11 and $13. Square, founded in 2009, was valued at $6bn after its last funding round a year ago. The firm expects to raise more than $403.7m, and had initially set a fundraising target of $275m when it filed for the offering on October 14.

Vodafone took inspiration from pharmaceutical companies as it sought to put testing at the heart of the business and take its brand research "to the next level." Speaking at a Thinkbox event today yesterday, Vodafone's head of brand strategy, insight and operations David Still said the brand has been taking steps to gain a thorough understanding of its media ROI.

Black Friday has quickly become known for setting retail sales records, although the annual day of discounting is a recent import from America -- but it has also created stock and Web site headaches for retailers while costing them full-price pre-Christmas sales.

Marketers could be missing out on appealing to receptive consumers as new research dispels myths around the use of traditional marketing segments. Although some demographic groups continue to show a strong affinity with particular brands, they are often not the ones that marketers would naturally expect.

The new Music Stories feature allows users to share 30-second clips of songs from Apple Music and Spotify to the Facebook News Feed where they can be played. It is currently only available with Facebook's iOS app however the social networking company confirmed that it will add Music Stories to Android and desktop soon.

The wait is over -- this year's John Lewis' Christmas ad is finally here, telling the heartwarming story of a young girl who sends a present to a man who lives on the moon. The ad hits screens tonight, capping off a week-long tease that has introduced the #onthemoon hashtag on social media and in a 10-second ad.

It is understood that Unilever is briefing agencies on its digital roster this week. Cornetto unveiled a YouTube video in July about a love story involving two teenagers that enabled the audience to switch between two views. It was created by Mofilm and RSA Films.

The BBC has hit back at critics who say it should stop publishing written journalism online. A survey commissioned by the BBC has found that 95% of the public think it is important that the BBC publish written news on its apps and Web site, and more than three-quarters think it should keep doing so even if it makes it harder for newspapers to generate revenue.