The more times you type in a word, the larger it will appear. You can play with fonts and layout and colors all you'd like.
A few tips:
***copy your text each time you create one, because it will be lost if you go back.
***To put it somewhere else (like your blog) you need to (alt+print screen) and then open it from your clipboard somewhere else (I use adobe photoshop) and then crop it and save it as a jpg and then put it in like anything else.
Here, for example, is a wordle made from one of my favorite Anne chapters, 25 in Anne of Green Gables "Matthew insists on puffed sleeves" I just googled it and copied it from the text (provided by Project Gutenberg)
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I'm looking forward to doing it with my 6th graders, having them describe themselves in Spanish and then make a wordle out of it. I think it'll be a fun way to practice and reinforce vocabulary.