To the OP...You really do need to start using the search engine, this has been done before.
My answer to the question. When you can name all the drugs you use by their scientific name I.E pills=methylenedioxymethamphetamine(I prolly got that wrong lol) and when people look at you like wtf? when your talking about drugs.
Basically when you have a shitload more knowledge on drugs than the general drug using community. Usually this isnt a bad thing, but I keep most stuff to myself because I dont like to be seen as a "drug geek" Ive already tried educating my friends with harm reduction but most of them either dont want to know, dont believe me or dont understand so I just keep it to myself unless someone asks me specifically about something.