It looks like someone took notice of your Google query results for the string: "Yahoo"... Searching for it today brings up all the normal, expected (non-evil) pages. This reminds me of the days when Google first hit the web and you could have www.microsoft.com be the first link ("I'm Feeling Lucky") when you searched for "pure evil". Similarly, www.sun.com would come up as the first link in a search for "C Programming". Anyone else here remember those publicly denied jokes (c 2000)?

Exactly which Google results for Yahoo do you mean?