Keen! That was the way that I remembered it and wondered where the controls were. Turns out they got lost along the way. Tribe.net has many content boxes (rss and groupings of tribes being the most noteworthy) for both your public profile and private home page. Which is quite useful, even if it does enable the occasional eye-bending page.
Multiply 'Customize Site' mode
The Multiply Blog - Coming Soon: New 'Customize Site' mode: "That's right, you'll be presented with controls for all of the editable elements on the page, from your content boxes to your headshot. Handy links for further customization (themes, layouts, CSS) are available at the top of the page."