The PokéCommunity Forums does not have a visible privacy policy, but we do wish and expect that you would keep information that important to you, to yourselves. This includes phone numbers, addresses, names, email address, IM handles, online game nicks, Friend Codes and anything else that is personal and can act as a way of contacting you. You are allowed to disclose such information if you so please, but you are under no such obligation and it is your responsibility to keep such information private or public if you want.
That said, the reason I bring that up here, in Other Games (as personal information is relevant across PC), is because of online games and Nintendo DS Friend Codes. For the time being, there will not be a large thread for you to post your Friend Codes in to act as a directory. Nor will you be allowed to post your Friend Codes in public through threads or posts. You are allowed to share your Friend Codes; I simply ask that you be careful about it.
You may give your Friend Code out to whoever you please, but through PM or IM or any other way where it would be that person and that person only who sees your Friend Code, not every member. This ensures that only those who you want to have your Friend Code will have it, and those you do not will not. I am concerned about this, because Nintendo is.
At the time of this post, the main concern would be Animal Crossing: Wild World. If you are not careful with whom you give your code out too, and whom you let in, then there could be trouble. People could post inappropriate messages on your bulletin board or using letters. They could also cut down all your tress and destroy all your flowers. However, more games are on the way and more problems are likely to arise.
All I ask is that you are careful with who and how you disclose such information.
Moreover, the best way that I can see is through PM, not posts and threads! Act smart, stay safe and you will have a more enjoyable gaming experience.