I used Wordle in a previous blog post, not realising it was one of the official Things.
Wordle lets you generate word clouds using either your choice of words, or using text it takes from a website. I created the following by entering my blog address as the URL:
On a similar note, Thing 20 is Tagxedo which also allows you to create word clouds in the colour, font and...wait for it... shape of your choosing, such as:
How great is that? Plus: