The commons is the web itself. This is hacker news, we click links on different domains a hundred times every day. Each of those sites could charge you for all their content but then you'd be broke or nobody would make enough money to keep the lights on.
As for the technological means to mitigate that; they aren't at all feasible yet. So the reality is most people support sites by viewing ads and those that don't view ads aren't supporting them at all. Most people, if forced to pay for certain content, just wouldn't bother because it's not worth it for them. I feel like that whenever I hit a paywall limit from a HN link; I enjoy the content but not that much overall.
