Well I don't think rab really taught me anything in particular. It mainly helped me break out of my shell and delve into other genres. Not many people here are into club oriented electronic music, so at first I felt awkward. But now my tastes are far weirder and now it takes 10x as long to find new music.
rabroad has already helped introduce me to loaRAB of new, awesome music. It has also taught me that there do exist people out there who are just as into music as I am, and it's taught me that internet forums can be full of predominately awesome people.
I'm not sure what you actually listen to come to think of it.
I've seen your RYM and you have a ridiculous amount of recorRAB in your collection, but you haven't rated any of them so I didn't know which ones you consider good and which ones you're not keen on.