I discovered Brickset only a few months ago and I've learned a lot of things so far. I'm going to share three of them in the hopes that they will inspire you to comment or to share your own experiences. I'm keeping it down to three so I hopefully can't be accused of posting a blog. (Have mercy on me Brickset gods if I unknowingly commit this transgression!)
1) British people play with and collect Lego! Silly, I know, but I just never thought about anyone else outside of America playing with Lego, even though it's not really an American product.
2) Only Americans call Lego Legos. (You will notice I try to use "Lego" now, but I will still refer to them as "Legos" if we ever talk face to face, just out of habit.)
3) There are Lego enthusiasts who collect polybags. When I read those articles about the subject, I bought the Gandalf polybag I had been intentionally passing over because I already had a Gandalf.
I have many more but I'll stop there. So, what have you learned about AFOL Lego from reading Brickset and the Brickset forum? (I have to sneak in one more: some AFOL have a chrome fetish!)