Earlier quoted context omitted.
Not that I know any Haskell, but wouldn't smallerSorted already include x due to edit: also, how is the pivot element selected there?
Both of your questions have the same answer. (x:xs) means x is the first element and xs is the rest.
Obviously picking first element as pivot makes for a very poor Quicksort. Though I presume a better approach, say median of first, mid and last elements, would add but an extra line?