That's a great contribution and really worthy of a blog post in it's own right.
But what's with the first (single word) paragraph? It seemed to me as particularly arrogant... really threw me off. I'm sure I misunderstood you intention, but it almost prevented me from reading the rest of what you had to say.
"This" as the start of a reply is shorthand for "the comment I'm replying to makes a very good point that I agree with entirely" (and usually "and here's my take on what (s)he wrote"), rather than "what you are about to read is the answer you are looking for".
It is a +1 mechanism for places that don't have voting, so far as I can tell. I have seen it quite often over on reddit. It used to be rather frowned upon here but the removal of visible vote numbers is likely to encourage it.
Basically what stonemetal said. With no vote count, it's a visual indication that I'm in agreement with what the person I'm replying to has said, and extending upon it.
But what's with the first (single word) paragraph? It seemed to me as particularly arrogant... really threw me off. I'm sure I misunderstood you intention, but it almost prevented me from reading the rest of what you had to say.
But I'm glad I got past that.