sitefinitysteve

...How does the route know to call the "PlacementsController" class?  Is it literally just removing the word "Controller" from the class name?

Yes.

sitefinitysteve

2) How do I create my own Restful verbage?  Like with Rest Preview I could design the Uri and map the querystring\other parts back to variables.

With WebApi, accepting URL paramaters and query string paramaters are both done with model binding -- this means you can just accept paramaters in your action method and they are mapped from those two sources. If you want additional dynamic segments in the URL you do have to modify routing to indicate those.