As they play students help to build up the thesaurus of words too, and there is also a simple search to help them look up words.
Tis would be great for ESL / EFL students as it is an enjoyable way to learn and extend vocabulary. They can look at other words people have associated with the words they know and try to deduce the meaning of words they don't know by looking at the other associations.
That make sense?
Give it a try and you might see what I mean.
As ever be careful of those words that ESL / EFL students love and we pretend we don't understand.