Semantic Link might be very useful for a discussion in linguistics. I found it trying to find words to use for a flash fiction piece I was writing. I was disappointed when submarine was not one of the words associated with yellow.
Word Wizard. I like that.
Visuwords is very pretty.
Overall, though, it isn’t as useful or as interesting as I had hoped.
Snappy Words is similar to Visuwords, but it has more parts that I found interesting. Plus it lets you wrangle the connections.