But not as advanced as Age of Empires
Information is Beautiful, a data visualization site run by one David McCandless, has charted the relative sizes of the codebases of some notable games, machines, and computer programs. Visualized in terms of number of lines of code, it's an interesting look at just how much programming's required to make things run.
Populi, at around a half-million lines of code, beats out the Space Shuttle by a cool 100,000 lines. TAKE THAT, NASA.
Granted, that's a bit of an apples-to-oranges comparison—the Shuttle software was designed in the late-70's and early-80's for the high-end computers of the time. A more apples-to-apples comparison would measure Populi alongside another modern, complex, person-centric app driven by a relational database. The only other thing like that on here is... Facebook, weighing in at around 61 million lines of code (and one-point-something billion users).