Google co-founder Sergey Brin is worried about the future of the internet, and not just because of censor-happy regimes like China and Iran. In a new interview with The Guardian, Brin told interviewers he believed "walled gardens" — like those of competitors Apple and Facebook — threaten innovation and risk splitting the open web into competing platforms. Brin notes that he and Larry Page wouldn't have been able to build Google if everyone refused to allow the search engine to crawl their sites, although competitors might argue that increasingly specialized apps are starting to obviate the need for generalized web search. The article is part of The Guardian's special series entitled Battle for the Internet, which includes a great interview with Ricken Patel, co-founder of Avaaz, on securing the open web against governments that would prefer to lock it down.