I see so many great reviews for providers from there. But when it won't let me join the site. It asks for a "reference" number on the main page when filling out the form. Anyone know how to join? Where to find reference number?

Use the following link to check out their website.  You can join there if you want.  Most of the women are young, pretty French-Canadians and YMWV.  I've been with a few of the C-N providers and the performance has usually been above average though I would suggest getting in early in the day as they book the shit out the girls and they tend to get hurried and/or cranky as the day wears on