I'm confused about the white list.  If i belong to a verification site does the white list substitute for a referral or will I still need a referral? If the latter please explain what the point is of the white list.  Thanks.

unless a client reveals his TER identity to a provider.

Even then, the provider has to know that the person showing up at her door is, in fact, the TER member he says he is.

It is not a substitute for being screened; it is only a bit of assurance that this client behaves himself and is liked by the gals who white listed him.

She can check with those providers and ask, I presume.

A client can PM a provider to prove his idenity to that provider so she may note his White Listing.  It may complement her screening & raise her comfort level.  
skb

Makes it easier for the provider to contact those providers on TER who are members of the community and gives them the chance to talk to them on here instead of having to call them and ask for the guys references, and info about is he recommended or not.

The girl can see if the whitelist he has are reputable providers or not and determine if more or less screening is done

whitelisting also helps the provider out, specially for guys that read reviews constantly or guys that join in the discussion board b/c you make click on a reviewers review history and see who he seen and a whitelist referral provider you may not know anything about or never heard of her or seen her advertise, all of a sudden become an interest to you and possibly add her to your favorites list.