America Online Inc, Vienna, Virginia is diversifying to protect its turf with acquisition of two companies specialising in software for the Internet. It is paying a total of $35m in shares for BookLink Technologies Inc, which does Internet access software, and NaviSoft Inc, in Hillsboro, California, which designs tools for publishing on networks.America Online plans to offer consumers separate access to the Internet early next year, in addition to the route via its own on-line network.