I'm proud for 2 reasons. First of all, K2 is used by one more big company. And it's not just any company. Citrix/Cloud.com are top at what they do. Secondly, it's because Cloud.com just got acquired by Citrix for a whopping $250 million deal.
It's probably the first ever acquisition deal we've ever heard of that magnitude that one way or another involves Joomla in. And not just that, K2 is at the heart of Cloud.com :)
Check out their site: http://cloud.com