Heh, nice. Here are the actual definitions courtesy of the Big Model wiki:
Gamism/Step On Up:
http://big-model.info/w/index.php?title=Step_On_Up&redirect=no
Narrativism/Story Now:
http://big-model.info/wiki/Story_now
Simulationism/Right To Dream:
http://big-model.info/wiki/The_Right_To_Dream
Basically, in a nutshell, "Gamism" is about overcoming challenges and doing strategic play in a risk/reward style of game; "Narrativism" is about eschewing any kind of predetermined plot (think of it as the polar opposite of Railroading) and focusing play on visceral human issues like emotions, relationships, and moral dilemmas; and "Simulationism" is about exploring the features and themes of a setting or genre.
By these criteria, 4E is fairly difficult to do Gamist play compared to other versions of DnD because of its focus on encounter-based design and little in the way of long-term strategic planning (although there were modifications such as those of the Fourthcore communities that tried to focus the game more on Step On Up play); 4E can be tilted to Narrativist play with fairly little work through its reward cycles (Quest XP and Skill Challenge XP specifically), explicit allowance of player-authored content and "reskinning", and broader conflict resolution mechanics compared to other versions of DnD; and 4E is generally pretty well suited to Simulationist play with the explicit understanding that what it is attempting to "simulate" is the heroic fantasy genre, especially as represented through cinema.
Hilariously, this is the OPPOSITE of understanding of 4E in most of the internet, with the understanding that it is super-Gamist and anti-Simulationist. The irony of this is truly astounding and speaks to the general ignorance and misinformation inherent to such discussions.
Interestingly, in his most recent Phenomenology series Ron Edwards has actually dropped Right To Dream as a creative agenda (presumably because setting exploration is something that happens in ALL roleplaying games, regardless of creative agenda) and only currently recognizes Step On Up and Story Now.