...aand welcome to the forums, fellow member from Japan! Omg, Japan is such a wonderful country, actually have a Japanese classmate and he's really quiet but is very nice. :) .. Visiting the Poke Center must be really amazing, every Pokemon fan wants to go to such place! And your a very lucky fellow.
If you were a lurker before, then I'm sure your already quite familiar with the board? What board are you usually checking in? Well, to give you a formal introduction to the forums. Basically, as what as my friend Megan told you above, we discuss Pokemon - a lot! You could find topics that are also not related to Pokemon, in which in other words, PC is diverse. I can also guarantee that you will make a lot of friends here, PC is a place wherein you could meet a lot of Pokefans and make friends with them. So don't worry about it too much, I admit that it would take time, but as you keep on participating on discussions and the like, you'll be able to meet some!
Feel free to ask me any questions if you have some, or you could also ask some of our intelligent and friendly staff, those whose usernames are usually bold and colored. If you still haven't read the rules by the way, then go read it now, you don't want to get into troubles right? With that, enjoy your time browsing PC! ^^