The new version of the word game will offer continuous play. That means if you start a game on your iPhone or Android device, you can continue it on Facebook, and vice-versa. The Facebook version will also notify players when it's their turn, or they've been invited to a game. A recent update to Words With Friends allowed you to challenge your Facebook contacts to a game, but this is the first time the game will be available on Facebook itself.
It is also the first time Zynga has brought a mobile game to Facebook. The company's best-known games, including FarmVille and Mob Wars, began on Facebook. There's no official launch date for the Facebook version of Words With Friends, but it could come as early as this week.
Words With Friends was introduced in 2009 by startup Newtoy, which was snapped up by Zynga when the game became wildly popular. It's a variation on Scrabble, with added chat functionality and a very relaxed two-week time limit for moves. Users can play up to 20 games at once. There's a free version for iPhone, iPad and Android with ads; the iPhone and iPad have ad-free versions for $1.99 and $2.99 respectively.
The official Scrabble game is free on Facebook, but costs $2.99 for the iPhone version and $9.99 for an iPad iteration. There is also a free Android app.