No Parcel Find Type Setting

I was curious if people don't bother to set their parcel "Find Type" for any reason beyond the fact that they don't advertise in "Find Places"? Currently my project surveyors seem to be finding about half (216 out of 450) of the parcels have no setting:

http://slhandbook.com/parcelbrowse.asp

I have done a random check and find that at least some of these "None" parcels are actually listed in "Find Places". I was just hoping to get some insight into why you wouldn't at least choose the most relevent setting regardless of advertising. Do many people ignore this setting as they advertise in the Classifieds?

I'm also curious if people who do use the Classifieds but not Find Places advertising if they get a better rate of click-through with this method. In building a directory either in-world or out, what is the best way to let people find your location if that's your intention?