It is a site that men can join so providers know your are safe for them to see.  The site verifies that, for the most part, are not LE.  It's like DateCheck and Room Service2000 aka RS2K.  These are the 3 big sites that we guys use mainly to let providers know we are ok guys when we don't have provider references to give out.  We guys can also use these sites to scout for providers in our areas.

If you are contemplating joining any of these, find out which is most popular in your part of the country.  It does vary from state to state.  As an example, in Florida where I live DC and P411 are much more widely used than RS2K, whereas in the midwest, RS2K is more widespread.  No sense joining one particular site if it's not used where you live.

Swim

for many hobby related terms. Also this web site link below is helpful. If you've haven't read the self help center, upper right hand corner of the main page, near the life preserver I suggest you should take a look. Finally, scroll 5 or 6 pages of this board, most questions pertaining to the hobby have been asked.