The Wii U's social network, Miiverse, will have a filter to block spoilers and adult language. In addition, each post will be read by a Nintendo employee -- screened, in essence -- to make sure it is appropriate for all ages. This human screening will be augmented by a computer screening process to get rid of obviously offensive content.
I understand that Nintendo is trying to maintain a family-friendly platform, but the whole point of this sort of service is instant feedback from other users. (Iwata even acknowledged that point.) Rather than going on about how ridiculous I think this is, and how it seems like Nintendo is doing even more to alienate their adult fans (who I'm not sure would even use this feature much), I'll simply say that I don't really agree with Iwata. I should also point out that there were no specifics on how long the wait would be on seeing a post go up, and it may not end up being that bad.