Every element is a node.
Every piece of text is a node. Even comments are nodes!
A node is just a piece of the page. And as in a family tree, each node can have children (i.e. each piece can contain other pieces).
Updating all these nodes efficiently can be difficult, but thankfully, you never have to do it manually.
Instead, you tell Vue what HTML you want on the page,
in a template:
So in normal circumstance, you could write
<h1>{{ blogTitle }}</h1>
but with Vue createElement you could write it like this
render: function (createElement) {
return createElement('h1', this.blogTitle)
}
and both would return the same result