It's funny that you ask how we have discovered LPL, because I think if you are a Linkin Park Fan that uses the internet on a regular basis there's no way to not discover it. The moment you meet other LP fans online sooner or later someone will mention LPL. I mean, LPL is one of the biggest websites about Linkin Park, in addition, it is the only guide for LP live shows. So that's my answer, I've discovered LPL by simple word-of-mouth advertising :-)
As to the second part of the question, there's just a ton of information about LP collected here, so that's why I joined the forum.