Third-party cookies that track the behaviour of web users are on their way out, but it is not yet clear what will take their place for online marketers, says Valentino Volonghi, "chief architect" of advertising platform company Adroll.

"One of the big trends for 2014 is the disappearance of the cookie," says Volonghi. It is a trend that is already under way, as mobile devices give inconsistent support to third-party browser cookies, and Google is now reportedly moving to take control of targeting techniques via the rumoured Google AdID system.

"Google and Facebook and Twitter have, understandably, built up profiles of users. But will they keep that information to themselves or make these IDs open and accessible to advertisers? It seems like everyone is sitting on the fence," says Volonghi.

AdRoll, which employs 30 people in Dublin and plans to hit 100 staff by the end of 2014, helps businesses chase customers online by targeting ads at users who visit a site but fail to convert their interest into a purchase.

As a “neutral” player, the company, whose headquarters are in California, naturally wants profile data to be available across all devices, from web to apps – a move that might also allow consumers to control the privacy settings for their entire digital experiences with a single click.

Online ad targeting has, to date, been a “confused” and “complex” affair, according to Volonghi. “It is hard right now to properly track conversions, because the world is very noisy.”