I have those same questions. The only answer was that it wasn't covert...there was no qualification or explanation. It seems like the administration's decision to brief only the chairmen and ranking members speaks to some kind of classified protection but I don't know.
At the end .. when Negroponte talked about how everyone on the panel took an oath to uphold the law .. he also mention that the Attorney General would address this further next week (Monday)
Also .. another thing that caught my attention was Rockefeller saying that only 4 members of the 535 members of Congress knows the most extensive effort of our intel in the NSA
He seemed to be trying to make a case that he believes under the law more members of Congress should know what is going on