It's fun, it's easy to play and it's got the kind of interface that feels very simple but actually has insane attention to detail.
Edit: You don't have to use only contiguous letters, if you've played a lot of Scramble that may take some getting used to.
(Sigh... should have spent more time studying design / HCI in school...)
[1] http://www.amazon.com/Design-Everyday-Things-Donald-Norman/d...
https://itunes.apple.com/us/app/letterpress-word-game/id5266...
Now, is it possible to write an AI? Sure, and actually, an AI-contest for this game would be a whole lot of fun. It's not simply "generate words" - you could give everyone the word list and the game would still play well.
Play a couple rounds with words like 'tetrasyllabics', where you completely reverse their blocks, and people just give up :(
Actually, I'm hoping there's someone else out there doing this too, because then I'll need to throw in the blocking logic.
I'm going to love this game right up until someone else creates a cheating app/site.
Seriously though, cheating apps totally ruin these word games. I remember loving Scrabulous (remember that name?) right up until everyone figured out how to cheat. Then the game just became tedious. Hopefully the tile-taking mechanic in this game will introduce enough strategy to keep play interesting for a while.