To add to all of this speculation is a post on GameCubicle.com which seems to suggest various marketing ploys and campaigns for such a feature. The most prominent seems to be the picture of a young boy in the woods holding a Nintendo DS. Going further, it seems that the words, "Find Me" seem to be a big part of this rumored campaign. In addition to the lone boy in the woods, there are images of puppets (marionette) with the words, "Find Me." Think of the word "marionette"....Mario Net? Yes, it would seem a great marketing ploy to suggest that stringed marionettes are the image we'll associate with Mario Net.
Going even further, it seems that in the words, "Find Me," there is a faded "s" after the "d" and before the "M". In other words, "FindsMe" with a faded "s". The middle of that phrase is now "DS".
And, why not add one more myth to this growing story. It seems that there is also a lot of reference to the 15th century explorer, Magellen, who was the first to circumnavigate the globe. Perhaps Nintendo will be suggesting that the DS will be the first network to do the same.
Hmm? Well, it would be quite an amazing feat if Nintendo could pull this off and if it did actually work. Then, you'd have free world-wide long distance in addition to a great gaming platform.
Again, don't believe any of this until you hear confirmation. It is very fun to think about but don't get too excited.