[Threshold]

I think this is a very fine line. The comparison above isn't quite applicable, since at least a graphical trailer for a graphical game uses the same medium as the game to attract players. And even then, sometimes games do worse than they would have precisely because they raise expectations too high with trailers and intro videos that the game itself cannot live up to.

But like I said, it is a fine line. There is definitely a certain level of graphics (or sound for that matter) that can entice and maintain interest. An especially good client that provides some sort of graphical interface for the entire game creates enough continuity between the graphical web site and the text based game that the player won't feel "tricked."