Yandex has waded into the ad blocking debate by opening up its Android browser to third-party ad blocking extensions. It has released an API for ad blocker Android developers, and has said it is considering doing the same on iOS in the future. Ad blocker developers who want to check the compatibility of their extensions with Yandex's Android browser are advised to use the “Content Blocker API”. Yandex is one of the most popular internet companies in Russia and its Android browser has around 5 million daily active users. Ad blocking has become extremely popular in recent years. Users install them for a variety of reasons, for example because they find adverts annoying or because they are worried about their data being collected.