These guys radiate a kind of aura, they have a stature. Maybe being an actor helps. But John Romero (third photo) is not an actor, he is a game developer who has designed Doom and Quake. Maybe because of Romero's personality or simply for fun, Romero's team decided that in order to finish Doom II, the player had to shoot Romero's head in a secret room of the last level (see screenshot nearby).
Currently, he is working on a MMO for Slipgate Ironworks to release in 2010 a
In fact, Romero has such an aura that he has been at the center of a controverse concerning a game called Daikatana. The advertising (see image nearby) was a bit provocative and the game develoment took a very long time. Whatever the gossips about him, Romero definitely has an aura. It is up to Slipgate Ironworks to use it for their MMO launch campaign, but I believe this aura can impact a lot.
In-game famous MMO characters have sometimes been personified by game developers. For instance, Lord British in Ultima Online was played by Richard Gariott. The name became so famous that Richard Gariott retained the trademark rights on it and reused it in Tabula Rasa. But most of the developers stay in the shadow and play the game anonymously, like WoW producer J. Allen Brack who plays anonymously with his father.