You'll find activity streams throughout NationBuilder. The biggest and most comprehensive of which is on your dashboard in the control panel. This stream gives you an overall, up to the minute view of everything happening in your nation: who is creating pages, who is tweeting about broadcasters, who is signing up on the website, who just left a voice mail, etc. More specific streams based around people and pages appear in other parts of your control panel and public website.

All of the activities that appear in streams can be edited when you go to Settings > Activities in the control panel. On the right hand side of this page you'll see a series of columns. Each column is a different dashboard in NationBuilder and you can control what streams a particular activity appears on by going to the activity and clicking on EDIT. There, you'll see check boxes on the right side of the screen where you can choose what dashboards the activity appears on. 

When you create new pages for you public website, you have the option to check Show stream in the Settings tab for that particular page. If you add a stream to a page that stream is a public dashboard.