With convention

Any type of object that satisfy the condition

typeof === "object" //Excluding strings, booleans, numbers, etc

Can be bound to a arbitrary element but the element in question must contain children.

<select data-name="items" data-bind="optionsText: 'name', optionsCaption: 'Select...'"></select>

<div data-name="selectedItem">
    <span data-name="name"></span>
</div>

http://jsfiddle.net/C5sGY/5/