According to him, just because TSW is lacking levels doesn't mean that you'll soon run out of ways to advance your character: "Collecting powers and building these decks of seven actives, seven passives, is a large part of that, and it'll take players hundreds and hundreds of hours to create enough decks to tackle most of the content in the game -- and that doesn't even take into account PvP."
Because players will be locked into a faction, Funcom is working hard to keep the balance of skills similar between all three secret societies. Even so, there will be abilities unique to each side.
Interested in Funcom's use of alternate reality games (ARGs) as part of The Secret World's experience? It looks as though these will be a bigger part of the game than we previously thought: "In fact, with our investigation missions, players will have to go outside the game in order to solve intriguing puzzles based on real history, myth, legends, conspiracy theories, and they'll also need to cooperate with other players via forums or chat in order to basically solve these really deep and complex ARG style problems. Some missions are designed to take weeks to crack, even with the help of the entire community."