Population size is not nearly as significant as you think.
Look here: http://www.surveysystem.com/sscalc.htm
A population of 10,000 needs 95, anything over 100,000 needs 96. 95% accuracy with 10% margin.
Now the sample is another issue, since the forum people are a special bunch.
Sill its safe to say that that the majority of the forum members are happy with the direction smartthings is going. 65% with a 10% margin of error still puts worse case at 55%.