Here are a couple of threads to read on the benefits of p411-
http://www.eccie.net/showthread.php?...highlight=p411
http://www.eccie.net/showthread.php?...highlight=p411
p411 is great and I've used it a lot, especially when traveling. It's based in Canada, so you don't have to worry about it being taken over by law enforcement. Most reputable providers will ask for references, but if you request a meeting from your p411 account, some will see new members without additional references (newbie friendly).
Once you have seen a provider from p411, they will give you an okay if you are a good boy (well-behaved, good hygiene, show up on time, etc.). These okays let other providers know you are safe to see.