I have an article in the current Guardian Weekly which looks at websites that allow learners to work with words (read it here). It mentions the following sites:

• Wordle: I’ve written about this site before (see here, here and here)
• Wordia: I’ll be posting a full article about this recently-launched video dictionary on teflclips in the next few weeks.
• Wordie: This site allows learners to create their own word lists. ‘Adjectives with two syllables that end in -y‘ is the example wordlist that is mentioned (see it here).