Yeah, in the blog post Jason added the example of our thank-you cards, but I personally think the actual product design is even more important. Kevin gives some examples in his "Designing Web Apps Users Love" presentation:
Totally agree. Wufoo has so much personality it would take an entire series to write about them and I didn't think it'd be fair to the other websites. =)
http://www.siliconprairienews.com/2011/09/sunday-video-wufoo...
Edit: Also, thank you! It's always nice to hear feedback from people who use Wufoo.