If you don’t like a single poll because of a dinky sample size, look at the realclearpolitics average of polls of the Republican electorate:
Newt is still in 3rd place, but it’s a solid 3rd, while Cain is drifting downward & Romney is at stasis. This signifies something important, unless you think McClatchy/Marist, CBS News, USA Today/Gallup, NBC News/Wall Street Journal, ABC News/Washington Post & Rasmussen Reports are all skewing or fabricating their polling data as part of a grand anti-Cain conspiracy.
Cain went from 26 to 22, Romney went from 25.5 to 22.5
So Cain drops 4 points when hit with wall to wall negative coverage and 5 woman sex scandal which turned to 4 and now is 3....
Romney, during the exact same period facing no scandal charges, using the poll YOU linked drops 3 points It does signify something important, unfortunately it appears you are not seeing it.