I always thought Pownce was a solid product. Design, UI/UX, the site copy and marketing - overall I thought it was really well done. If it wasn't for the overwhelming success of Twitter or how easily Facebook launched the same features, things could have turned out much differently for them.
It wouldn't surprise me if within 3-6 months, Six Apart launches a rebranded version of Pownce geared towards companies and enterprise to compete with Yammer. As much as it pains me to agree with Arrington and Calacanis, I'll admit that Yammer has a good business model. And I can't imagine that it would take a tremendous amount of development time to make Pownce ready for those types of customers.