my lightning round 4 question, restated

[mr.b]

I didn't get my meaning across in my original question found here:
http://www.wickedfire.com/showpost.php?p=24399&postcount=48

you answered, here:
http://www.wickedfire.com/showpost.php?p=24416&postcount=59

but what I was trying to ask, was:

what is a good way to judge the viability of a niche in the 3rd tier networks (does the niche get enough traffic to make it worthwhile to test)? What numbers do you look at and what numbers do you use as a baseline?

thanks,
_b