I placed an ad in our local newspaper and website, and met my husband through the ad. I would say that about 12 men responded to the ad by leaving a voice mail message. Only 3 of the men seemed interesting enough to contact, 2 of which seemed worth meeting in public. The first turned out to be a big disappointment, and the second I married. Of the 10 that I didn't consider, I would say that 3 seemed like nice guys, but not for me and the other 7 seemed like weirdos to me or very inappropriate for one reason or another (for example, I was 34, and one of the responders was 76, and another was a 17 year old college kid).
My younger sister is normal weight, and very attractive, and traditional dating hasn't been much different for her. The big difference seems to be that personal ad dating tends to be a larger number of people in a shorter span of time. You need to take precautions, but they're the same precautions you should take if you met a man randomly in a grocery store or night club. The "worst" dating experience my sister ever had (crazy stalker) was actually set up by a mutual friend.