The latest "Path to Free to Play" blog post on the Star Trek Online site deals with a new feature introduced on the Tribble PTS: Dilithium.
Dilithium is now a new form of currency for players to collect. Dilithium can be earned through "ranking up" in level. Each level gained yields a cache of refined dilithium. In addition, there are several ways that players can earn dilithium ore which can be refined at a later point.
The blog post also goes into some detail about the sorts of things that dilithium can be spent on.
Read the entire blog post on the Star Trek Online site.
Thanks to Piasek for the tip!