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)
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.