it's.... it's.... it's... Evernote! Yes, Evernote is turning into a knowledge management powerhouse, and by opening up Evernote Business, it's making first serious entry into the business.
One of the things (or The thing) making Evernote a good product has been its attention to details. And Evernote delivers here as well. They realize that people are going to be using it for both personal and business needs and finds an elegant balance of integrating the two together by doing cross-searching but keeping good controls over what's shared and what's not.
Cost? $10/user/month, not bad for small organizations of 10-20 people..
The Wiki market just got more exciting!
Standard Evernote intro video below: