Everyone speaks emoji, and now advertisers do too.

Catching on to the digital era's cross-cultural language of choice, advertisers have learned to speak emoji in a world where promotional videos are ignored and ad banners are blocked.

Tiny digital pizza and French fries icons, and pictures of animals and planes are being used to advertise fast food, airlines and even NGOs.

Emoji characters have become at least as pervasive as smartphones, and users are moving away from communication platforms that allow advertising towards networks that don't, said Marie Dolle, a digital media content specialist at Kantar Media.

In their online advertising campaigns, the World Wildlife Fund charity and Domino's Pizza have tapped into the bank of emoji icons universally approved by the Unicode Consortium, the non-profit group that develops and maintains digital standards.

In May, McDonald's -- a pioneer in emoji advertising -- launched its own digital stickers package that allows users to pictures of Big Macs, sundaes and chicken nuggets into their Whatsapp, Facebook Messenger or text messages.

Disney and Duracell have commissioned Feeligo, a Paris-based start-up, to create their brand stickers. Last winter, Duracell's iconic pink bunny was shared 20 million times alone.

Swedish low-cost homeware giant Ikea also launched an emoji range depicting its products earlier this year, from furniture to the meatballs sold in its cafeterias.

'Less aggressive' than ads

Emoji advertising is just as much about communication and having a sense of humour as it is about branding.

"Stickers have to represent emotions. A logo doesn't work by itself," said Feeligo co-founder Davide Bonapersona, whose campaigns have spread to several European countries and which often cost clients less than traditional formats.

"Depending on the target, we are looking at 20,000 to 100,000 euros ($22,000 to $110,000)," Bonapersona said.

US-based Swyft Media and Asian messaging apps Line and WeChat share this growing niche market with Feeligo.

The latest advertising trend is mainly logo-free, giving emoji users on both ends of the chat more freedom.

"Users are saturated with publicity," Dolle said, adding that many people use free software that blocks pop-up advertising to keep their screens uncluttered by ad banners and videos.

Emoji is "less aggressive, it's not intrusive. We give them playful tools that they can choose whether or not to use. This contributes to making people love the brand and share it in their conversations," she added.

France's state-owned postal service La Poste has also launched its own stickers in the shape of personalised stamps to celebrate special days in users' lives, such as the birth of a child or a wedding.

The campaign has proved a major success, with the digital stamps seen by users more than nine million times, said Rassem Belhouadjeb, a member of La Poste's digital marketing team.

"We exceeded our goal eight times over," he said.

But emoji campaigns may do little to keep brands' foes at bay, as a prank by a graffiti artist in the British city of Bristol showed this summer.

The artist had some fun with one of McDonald's billboards, embellishing it with a vomiting emoji.