Nintendo 3DS, 2DS and DS

Inspired by this comment, I'm curious how many people play DS or 3DS online, or even older GB games by some virtual Link Cable emulation? (If that exists?)

Last time I played was RE Revelations quite a while ago, and that was pretty active. I wonder how it's now. I imagine people still playing Mario Kart.

While I'm too busy with other stuff at this time, I think it would be cool to gather information and resources and maybe coordinate some online games for the handheld lemmies.

It's also worth noting that 3DS is one of the newest consoles that still offers free multiplayer. I only have a PS3 and 3DS and as such, I still can't wrap my head around it that all the current consoles require a subscription to play with fiends. In other words, [email protected].