owldeath, it is completely different. Ask yourself this question first…How would you go about buying 1,000 links today? From one of those companies that has 1,000 sites all designed nearly the same, maybe hosted on the same couple of servers, maybe they just all happen to be linking out to the same group of sites (whoever pays to be linked). Google absolutely can tell when something like this occurs (I know because it came out of their own mouths yesterday).
Now, to the Katrina example, everyone naturally setup links to organizations that were trying to help, probably millions of new links pointing to the Red Cross for example. Google will reward the Red Cross with Katrina related search results because of this, clearly understanding that they didn’t go out and pay everyone to link to them because every site is completely different in the eyes of the search engine.
The same would hold true for a brand new site that set themselves up to help Katrina victims and received a ton of links overnight. Google likes seeing a bunch of links to a site, they don’t like seeing clearly bogus links pointing to a site, and yes they can tell the difference.
As for buying links, it is perfectly acceptable to buy a few links here and there, Google even said they don’t have a problem with that. They have been pretty publicly stating not to buy links, but that gets mis-interpreted by some, what they seem to mean is stay away from link schemes, which has always been a part of their webmaster guidelines.