Simple way to know if it breaks the NDA or not:
If the information/video/talk is on the official SE FFXIV site, then it's perfectly fine to post. If it is not, then it is a leak and is against the NDA to post it. Posting said leaks will get you bant.
This is not always true, we get information from famitsu and other magazines before the information is posted on the official SE FFXIV site.
As was said before, TkdGunter did not break an NDA by posting a link to videos, because he is not in the alpha/beta so he didn't sign an NDA (even if he filled out a Beta app, and agreed to the NDA, it only applies if he was in the beta).
But zam will not let anyone post information about FFXIV that is not from an official source sanctioned by SE. Threads that don't adhere to these rules get nuked, as this one would have if TkdGunter didn't take down the link. Edited, Apr 12th 2010 1:53pm by Cyiode