Welcome, Xander. Feel free to come to me with any issues or questions you may have. Basically, heres what you need to know about Serebii:
1: Spambots are evil. report them. always. use the little 'yield' sign thingy in the upper right hand corner of each post.
2: Posts = good. as long as they arent spam
3: read the rules of a subforum before doing anything else. You don't want to get in trouble by accident.
4: If you're looking for friends, head to a clan. My own, Operation Obliviate, is very good for that kind of thing.
5: Don't double post. You'll get hit by the mods.
6: Actually check the forums before making a new thread. See if there's already an existing thread about the topic you want to discuss. Also, when making a new thread, give the original post some substance. Don't call the thread 'I luvz Sinnoh,' with the original post reading 'I luvz Sinnoh. Discuss.' Try to use proper English. Your post here, albeit being a tad on the short side, is a great example.
I think that covers everything... If I missed something, a fellow poster will probably add on. Have fun, and again, welcome!
