What about "Was this trick helpful to You?" and record the number of people who click yes. Kinda like what they have for the reviews on amazon. I'd be simplier than the old system and posters whould know when someone appreciated the time and effort that went into the trick. Very hard for the twits of the world to skew the results as the worst they could do is not click yes. Users would also get some idea if it's a good trick worth working on or not.
Just a thought....