Without going into too much detail (for risk of providing information to would-be intruders), I can tell you that Planet Calypso Forum utilizes several additional security measures to protect forum member accounts beyond the standard vBulletin systems.
The servers on which PCF is hosted are very secure, and have never been compromised despite a fair number of attempts over the years.
Nevertheless, as a general security precaution it is very important never to use the same username, password or email address that is used for one's Entropia Universe account on other websites or forums, including PCF. And of course, everyone who values their Entropia Universe account should have a Gold Card.
Regarding the thread title: SSL would offer very little benefit in protecting forum member accounts, and would probably result in a slower browsing experience for members.
Most forum-related attack vectors focus on compromising either the web server, or, much more commonly, client browsers or computers, not on intercepting http traffic between client and server. Thus, employing SSL on PCF would offer very little practical benefit.