Several mobile operators plan to block advertising on their networks, setting the stage for a battle with digital media companies such as Google, AOL and Yahoo. One European wireless carrier told the Financial Times that it has installed blocking software in its data centres and planned to turn it on before the end of 2015. The software prevents most types of advertising from loading in web pages and apps, though it does not interfere with “in-feed” ads of the kind used by Facebook and Twitter.