If you have heard this taught in defence of the Trinity, then I would recommend reading it in order to keep your reading balanced and your own interpretation as free from bias as possible.
Trinitarians in examining the hebrew word for "one", will tend to infuse it with plural connotations based on usages in the Old Testament where it modifies a compound noun, approaches the task in a way that is misleading, in the same way that it can in presenting a one-sided view of the debates around "Elohim" (i.e. simply ignoring the pertinence of key Elohim passages like Psalm 82). The key and simple point that Buzzard powerfully demonstrates is that the word "echad" itself remains stable, whether referring to compound nouns (such as bagpipes) or simple nouns (such as bag or pipe).
Trinitarians really need to be more careful in arguing their case and transparent about their limitations.
Unitarians need to be careful about championing falsehood of Trinitarian claims based on single refutations such as this.