This is the location where a player can pay for Premium access to the website, either for oneself or for others. It contains some information about the benefits of a premium account, a link to pay via PayPal, and information on the Referral program. Note that your personal subscription information can be seen on the History tab of your My Games page.
Player attrition is the deadliest foe faced by this site. It's inevitable; over time, a certain percentage of our players will leave through either disaffection or disinterest, and some of us will face real-life events that leave us without the time or ability to indulge in the game. That's just life, and it's understandable.
But we as players can help the website and the game we enjoy by recruiting replacement players from among our friends and by posting links on social media websites. In return, we are given a reward by the Planets site for every recruit we sign up, and the top recruiters are tracked in the Leaderboard.
To access your personal link, just go to the Upgrade button on the top navigation bar of the web page, or click here. You will see a personalized web link which represents your own account; copy that into your post (or, if you're old-school, your email) for your friends to click.