Draw Something from OMGPOP, available now on the App Store in both free ad-supported and paid ad-free editions, has shot to immense popularity worldwide in recent weeks, topping both the iPhone and iPad charts.

The game is a simple draw-and-guess game where players compete against each other to create pictures based on stimulus words. There are a number of key differences from its competitors such as Charadium II and Chalk ‘N Talk, however.

First of all, gameplay is asynchronous rather than real-time. Charadium II offered an asynchronous mode which it dubbed “Ping Pong,” but its primary gameplay mode was based around real-time chat and guessing. Chalk ‘N Talk, meanwhile, offers only real-time online play, and is also blighted with a community which seemingly refuses to draw anything, instead preferring to play the game more like Hangman.

The second difference is in how the stimulus word is guessed by the non-drawing player in Draw Something. Rather than having to type the word themselves and risk spelling it incorrectly, players are provided with a jumble of letter tiles at the bottom of the screen and an indication of how many letters the solution contains. They must then simply spell out the word in order to succeed. If the word is correctly guessed, both the guessing and drawing player are rewarded with coins and the turn counter increases. Play then passes to the other player, with the aim being for the pair to cooperate to enjoy a streak of as many turns as possible without direct communication between one another. As such, there is no chat facility in the game.

The game requires an online account to play. This may be signed up for using either Facebook or an email address. If the former is chosen, the player can later choose a specific username and password to add additional security to their account. Connecting with Facebook aids with opponent discovery, as any members of the player’s Facebook friends list who are also playing Draw Something will be listed within the game. Like other popular asynchronous titles, however, it’s also possible to play against random opponents or challenge people directly using their username or email address. The game does not feature support for Game Center, OpenFeint or other online networks, instead using its own proprietary account system coupled with Facebook for its social features.

Both the ad-supported and ad-free versions of the game feature monetization of the in-game currency, which is used either to purchase “bombs,” allowing for the skipping of difficult words, or additional color packs to allow for more detailed, colorful pictures. Coins are earned at a slow rate through play, but impatient players can purchase large quantities of coins in packages ranging from $1.99 to $24.99 if they so desire.

At the time of writing, the free version of Draw Something is currently sitting in the No. 1 spot on the Top Free Apps and Top Free Games charts for both iPhone and iPad. The paid version is currently No. 1 on the iPhone paid apps chart and No. 4 on the iPad paid apps chart. You can follow its progress with AppData, our tracking service for iOS and social games and developers.