Are you referring to trade and such with normal player's or a MMORPG (Mega Multiplayer Online Role-Playing Game)? For the furthermost it would be a no. But for the first it may be possible if you are on a laptop that gets a Wi-Fi connection perhaps. I've never used a DS Emulator so I can't be sure.
I mean that i use my R4-FLASHCARD with a hack of Pokemon White with new evolutions/attacks/types (Pokemon Blaze Black).I can use WIFI but I dont know if I can trade/battle with people playing the original Black and White,thats the question