25,000?
If this number was even in the ballpark, I would have expected a lot more in the way of survivors or families asking about missing people - even more than after 9/11. I have heard some of these types of stories, but nothing like the volume or coverage after 9/11. Here's hoping.
They said there were going to be 200 dead in the superdome and there were 10, considering the flood happened during the day I would predict they the number for the whole region will still be lower than 9/11. 2,500 would be my estimate.
The Red Cross has established a Family Network at http://www.familylinks.icrc.org/katrina/people
A spot check (not comprehensive) seemed to be mostly people searching for other folks; I didn't find many self-registrations. I also started scanning just the name list, and assuming that names that include full addresses are more likely to be self-registrations and names that don't are more likely to be people searching for other people, then that matches my spot observations that mostly that these are "searching for" entries.
There are a lot of names on the list. I stopped looking when I paged through the first 1000 names, and I wasn't even half-way through the letter A listings.
However, there is probably no way for listings to be deleted or marked as no longer needed, so some percentage (hopefully very large) are no longer active.