what does the "loose geometry" do?

You can find it at “select>Loose geometry”
I saw it and i was wondering what it can do.
It may be useful for me.

So, do you know?
Please let me know.
Thanks!

Based on current selection mode, it will select:

(Vertex) Vertices not connected by any edges;
(Edge) Edges not connecting any faces;
(Face) Faces not connected to other faces.

“Loose geometry” are
a) vertices that are not connected to an edge,
b) edges that do not form a face and
c) faces that are not connected to the mesh.

From my understanding the Select > Loose Geometry is about getting rid of those stray edges and vertices that have been left behind during mesh editing. So, this is not so much about what loose geometry “can do”, but more about finding mesh errors and glitches.

EDIT
Stan is just too fast!

Thanks to both of you!