The big lie of computer security is that security improves by imposing complex passwords on users. In real life, people write down anything they can't remember. Security is increased by designing for the way humans actually behave. -Jakob Nielsen
We've done the best we can to ensure nothing will cause a half-secure connection (some non-SSL items loading), but some things still might. If you encounter any half-secure connections (excluding embedded images in forums posts), please be sure to submit a bug report.
Update: We've now employed a Wildcard Sub-Domain certificate across our SSL-enabled services (web, IRC, soon to be many more) that is Comodo-signed. This will enable us to provide trusted SSL communication encryption on many, if not all, of our services.