Apparently, it is a turn-based strategy with MMORPG influences.

According to Wikipedia:

> Drugwars is a turn-based strategy
> computer game in which the player
> assumes the role of a drug dealer. The
> object of the game is to deal the most
> drugs to pay off the "loan shark" (who
> charges interest) by the end of the
> game and make a profit.

And the Zynga variation:

> Zynga's rendition of Dope Wars took
> the basic layout of the original game
> and turned it into an MMORPG style
> game with user interaction.

[Source][1]


  [1]:http://en.wikipedia.org/wiki/Drugwars#Zynga_version