They announced this new feature on Battle.net. Here is an extract from the official announcement:
We’re adding a feature-limited web browser to World of Warcraft that will replace the in-game support system with a direct portal to the Battle.net Support site. Our aim is to give players in-game easy access to the site’s robust knowledge base and support contact system.
We’ve gone to great lengths to improve our website support systems and we want to offer access to all of its robust features in-game. The new browser will make it it easier to find information to help you resolve issues you’re experiencing or contact our representatives if you need a little extra help.
Please note that this in-game browser will only grant you access to the battle.net domain. It is unclear if the Blizzard will open up other external domains in the future.