It appears as if characters are universally somewhat short-lived (which I find interesting); exactly how short is this living?

At the low end, a character will live roughly 500 RL hours before expiring due to old age. (700 is more common, but we'll stick with the low end.) Most characters 'die' to deletion-- not many people stick with one character for 500+ hours. As a new player, age-death should be at the very back of your mind.

I notice that characters appear on the "Battlefield" forum with a certain number of hours listed as their lifespan; does this mean hours logged-on, or real-world hours since creation?

Hours logged on. So you'll get 500+ hours of actual gameplay for that character. One of the perks of this system is that it guarantees a certain rate of turnover-- depending on what other MUDs you've played, you may have seen games where the 'cool' jobs belong to characters that been entrenched for RL years, and there is very little chance you'll be able to work into those positions. Here, leadership positions often open up every couple of months.

Aside from that subject of characters' longevity, what is the gameplay itself like? It seems as if more of an urgent and action-oriented playstyle exists here, based on the game's PK-filled nature. Is playing this game equivalent to playing a text-based, role-playing version of Counterstrike, or is there a large amount of long-term building-up of one's character as in other MUDs?

All of the above. Roleplaying is our first and most important rule, and part of roleplay is conflict. Experience is most often earned through conflict, but characters also amass appreciable piles from roleplay rewards, quest completion, business savvy, exploration and observation, conducting successful battles against rival cabals, and more. Characters are expected to develop and mature, and the reward structures are designed to encourage that-- exceptional characters find themselves in the possession of extra abilities, custom powers (a mage might shapeshift into a griffon or other unique beast, someone might gain an ability possessed by no one else in the entire game, etc.), roleplay rewards (being known by a special title, being able to bring people in or out of a cabal, being in a custom-made quest designed by our staff, etc.), etc.

Sorry for the newbishness and, particularly, vagueness of my question; I will obtain some first-hand experience with the game as soon as possible, but as of now I'm just trying to understand what it's all about. Any general insight is appreciated.

All to be expected! We've been active for 13 years, and new tweaks large and small are made literally daily, so there's a lot that has accumulated over our existence. It's a large world with a lot of nooks and crannies, so you shouldn't feel expected to be an expert in a week, or even six months.

valguarnera@carrionfields.com