foxfirefey and marahmarie pretty much nailed it! The network is a paid feature because it's computationally expensive -- the reading/network pages are one of the three "big pigs" in the code in terms of how much server resources they take to generate. (The other two are comment pages with large numbers of comments, and accounts that have large numbers of icons -- although the icons are more a bandwidth drain than a server processing power drain.) So, we keep it for paid users. But because there are fewer paid users, and therefore fewer people whose network pages we have to generate, it doesn't actually cost us that much in terms of load to allow everybody to look at that page for the accounts that have access to it: once the page has been generated once it's way more likely to be stored in memory, so everybody can use the network page for the accounts that are allowed to use it.