Here's what I came up with, does it make sense?
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Content
Most jQuery methods that accept "content" will accept one or more
arguments of any of the following:
* A DOM node element;
* An array of DOM node elements;
* A jQuery object;
* A string representing HTML.
Example:
$("#div1").append(
document.createElement("br"),
$("#div2"), "<em>after div2</em>"
);
Auto-Cloning
Content inserting methods (append, prepend, before, after, and
replaceWith) behave differently depending on the number of DOM
elements currently selected by the jQuery object. If there is only one
element in the jQuery object, the content is inserted to that element;
content that was in another location in the DOM tree will be moved by
this operation. This is essentially the same as the W3C DOM
appendChild method.
http://www.w3.org/TR/REC-DOM-Level-1/level-one-core.html#method-appendChild
When multiple elements are selected by a jQuery object, these methods
clone the content before inserting it to each element. Since the
content can only exist in one location in the document tree, cloning
is required in these cases so that the same content can be used in
multiple locations.
This rule also applies to the selector-insertion methods (appendTo,
prependTo, insertBefore, insertAfter, and replaceAll), but the auto-
cloning occurs if there is more than one element selected by the
Selector provided as an argument to the method.
When a specific behavior is needed regardless of the number of
elements selected, use the .clone() or .remove() methods in
conjunction with a selector-insertion method. This example will always
clone #Thing, append it to each element with class OneOrMore, and
leave the original #Thing unmolested in the document:
$("#Thing").clone().appendTo(".OneOrMore");
This example will always remove #Thing from the document and append it
to .OneOrMore:
$("#Thing").remove().appendTo(".OneOrMore");
