I have to agree with Jeff. Why pay a monthly membership fee when, in just a couple of days, you'll see the ad anway? Also, if you noticed, you see the "members only" ads on 350, but you can go to one of a half dozen other sights and see the ad placed (or copied) there as well without paying the membership fee.
One I've found curious is the ad for YUM! Brands. It's been running for nearly six months (comes up nearly every day on FlipDog) and one person on this board claimed (I'll believe it until I see different) that he accepted employment with them some three months ago, yet the ad still runs.
2000Flyer