This is why I've started to dislike revisionist history. The premise that the threat of Stalin alone forced Japanese surrender is at least as ludicrous as saying that the nuclear bombs alone forced Japan to surrender. I closed the page immediately because of the full-page popup ad, but I've encountered the premise elsewhere so it warrants examination. The first thing to realize is that for Japan, whatever else happen…
The atomic bomb was not the deciding factor for two reasons: 1) the decision to surrender happened before the impact of the atomic bombs was fully assessed, and 2) the effect of the bombs was no worse than the massive conventional bombing that Japan had already experienced. The vast majority of Japan's large cities had already been pretty much destroyed by the time the atomic bomb was used: it was a "raindrop in a hurricane."