While free web-based challenges to Microsoft's wide range of productivity software have almost become commonplace (see: Google Spreadsheets, Writely), their enormously popular anti-productivity software (See: Minesweeper, Solitaire) have remained relatively safe... Until now.
In a single month, two shots have been fired across Microsoft's Programs / Acessories / Games bow. First came Gminesweeper, an almost fully functioning parody of Minesweeper. Now Adam Lyttle has released Solitaire Craving and, although he claims it is still undergoing beta testing, the flawless AJAX implementation and ingenious community-based design is sure to please solitaire addicts worldwide.
Solitaire Craving uses a Klondike variation, the rules of which are summarized here. Every day a new challenge is randomly generated and made available on the site. After completing the game users have the option to assign a difficulty level which, averaged with the input of all the other users, determines whether the game is archived as an Easy, Medium or Difficult challenge. This ranking system is reminiscent of projects like Peekaboom or The ESP Game and could actually end up helping to determine the percentage of unbeatable Klondike games (however, considering the vast number of decks available, this would still take quite some time).
Analysis: Solitaire Craving's interface is clean, smooth and easy to use, but the real draw is the emphasis Lyttle has placed on community features. Each game has a comments section, and a site-wide ranking system keeps track of each user's number of moves made and total time spent playing. As the site has been online for a little over a week the user base is still developing, but is likely to expand rapidly as word spreads about this fantastic free version of one of the world's most popular card games.