From the blog "Featured News"

UPDATE: The limited-time opportunity for existing Premium members to lock in their current rates for one more billing cycle, including extending an existing monthly to use the current full year rate by upgrading now to annual is now available on the premium page. Simply renew before June 24th to extend your current Membership at the same low rate. For example, monthly members will be billed at the lower rate for one more monthly billing cycle, while annual members may renew (or monthly users ma