The quandary for those who run social networks is how to monetise activity on them without antagonising and thus losing users through distracting ads? The answer, for Twitter, YouTube and Instagram, is to slip in some stealthy ads camouflaged to look like posts from listed contacts. Each of the networks has in-house teams whose job is to think up ways to advise brands on how to sneak their marketing into members' feeds. At YouTube, owned by Google, the effort is called "Zoo." Instagram uses the "Creative Shop" of its parent company Facebook. Twitter's name for it is the relatively straight-forward "Brand Strategy." The strategies adapt to the specific requirements, formats and behaviour on each of the social networks. In the case of Instagram, the four-year-old site which boasts 300 million users worldwide who share filtered photos and videos, the advertising push has now extended to France. The network long resisted introducing sponsored messages, aware that many of its fans were creative types - artists, photographers, architects - against having screens of pure images corrupted by tawdry commercial intrusions. But after Facebook bought it for $715 million in 2012, Instagram started putting in ads. They started in 2013 in the United States, then Australia and Canada in late 2014 and, from mid-March this year, in France. They hide in plain sight: presented in the same square format, with the same "vintage" filter as user-generated pictures. Only the mention "sponsored" reveals that it's there to sell, not share. In 2014, Zoo lent its talents to the Italian fashion company Fendi and the result was the first fashion show filmed with drones and broadcast live on YouTube. Laurent Buanec, brand strategist for Twitter, said: "Sometimes, we get ideas that aren't really feasible or which miss the point. Our role isn't to give scores but to accompany agencies and brands." One campaign rolled out with the help of Twitter was for Nissan France. During a UEFA Champions League tournament, the car manufacturer turned its Twitter feed into a football-stat spouting source during the matches - to emphasise the brand's sponsorship.