Technically no matter how big a chicks breasts are, they will fill the cups of the bra they are wearing (if they are wearing the proper size of course). However, at Filled Cups, they are obviously referring to chicks with larger breasts, just like the girls at Big Boobs Galore. I mention Big Boobs Galore because not only are they both big boob sites, but also they are the same big boob site.
Filled Cups is a nonexclusive site with loads of content. There are 39 categories of content. Iin the 'big boobs' section alone, you will find 1,098 sets of pictures and 1,049 downloadable videos. The photos are great-quality while the videos are average. The other 38 categories provide members with over 800,000 more pictures and 7,900 videos. The price tag is quite high, but for the amount of content available, it might be worth it for some.