The ESPN pact enhances the Nintendo Fan Network, launched in 2007 by Mariners’ majority-owner Nintendo as a means to deliver information via an in-stadium Wi-Fi Network to the fans using their portable Nintendo gaming devices--even allowing them to order concessions.
One, I always forget that Nintendo is the owner of the Seattle Mariners. I had noticed how Seattle always seems to have more Japanese players than average, but I just chalked that up to being on the west coast. If the Cubs deal goes through (my understanding is that it hasn't yet been approved by MLB, though I could be wrong), the Mariners are one of only three teams to be owned by a corporation rather than a single majority owner (the Atlanta Braves and the Toronto Blue Jays being the others).
Two, I wonder how popular this is. I wouldn't expect to see a lot of Nintendo DS' at a baseball stadium, but there are 100 million sales worldwide, and once you've been to the stadium once, you'd bring your DS along if you had one.
I guess I have no real insight into this, other than thinking that it's rather interesting.