We've just upgraded a part of our network infrastructure, and part of that upgrade is to enable SSL across all parts of Roll20 (the VTT itself, the forums, the Marketplace). The main info site (roll20.net), the Help docs, and the Blog are not SSL at this time, but cookies are now set to Secure so your session information will not be sent to those sites (as they are hosted on external services like Tumblr). Please let us know if you run into any issues with this, but it should be a seamless transition.