MMO Hub is discussing a hands on preview of the upcoming Star Trek Online. It's a good read.

At PAX, only the Starfleet gameplay was shown. In most MMOs, showing gameplay for one faction vs. another is mostly a matter of aesthetics, but according to executive producer Craig Zinkievich, “Star Trek Online's” two sides will differ quite a bit, with the Klingon gameplay focusing more on PVP, and Starfleet more on PVE.

What doesn't differ, though, is the importance of your ship crew. When you get a ship, you can make it look however you want; that doesn't do a thing other than change appearance. How you make yourself unique, and how you determine what your playstyle is like, is the way you handle your officers.

Officers act as both the modifiers for ships, and as partymates on planetary portions. On ships, your officers will grant you special abilities, boosts, and stats based on how you customize them. In the PAX demo, the tactical officer focused on combat, for example, and he gave a timed skill that let you fire two photons instead of a single one, which is default.