Haven't looked at all 145 pages of this thread so someone might have said this already, but not all of these girls have got small tits. These:
http://fap2babes.com/10576/angel-kiss-piney-sex/ for example are surely average if not slightly larger than average, looking to be at least a d-cup. I suppose it's a subjective measure though. If you're used to seeing massive tits all the time then I can see how anything non-massive would count as small.