Wordle is an excellent site for generating "word clouds" from text that you type in or copy and paste in. The clouds give extra prominence (make the word bigger) when it appears more frequently in the text you put in. You can change your clouds with different fonts, layouts, and color schemes. You can select it or change at random.
When you have completed your Wordle, you can print it out, save it to the Wordle gallery and email the address to your teacher. Wordle is excellent to use with poetry. By copying and pasting or typing in the poem, the students can see and discuss the prominent words, see frequency, and use the Wordle as a discussion point for the meanings of the word.
Wordle is free and you do not need a user account for it. So you don't have to have students register ahead of time, there is no registry. It's fun, try it.
How to Create A word Cloud