When calling

$(document.createTextNode("foo")).text("bar").appendTo(document.body)

The text is set to "foo" instead of "bar". One would expect that you can set the text on a textNode using .text()

see jsFiddle: http://jsfiddle.net/Raynos/PU4PX/2/

The problem lies here.

if ( typeof text !== "object" && text !== undefined ) {
    return this.empty().append( (this[0] && this[0].ownerDocument || document).createTextNode( text ) );
}

An assumption was made that you can append a text node to a text node. Which is invalid because textNodes can't have children.

One possible solution is checking for this.nodeType === 3 and using elem.nodeValue = text.

An alternative would be using textNode.data as seen here: http://jsfiddle.net/PU4PX/3/

I've only tested nodeValue in internet explorer and firefox.