I think the question of how many people of whatever age group lack basic information about OBL is intriguing and worth looking into, but the story's premise is hung on a very shaky frame.
For one thing, the photo of tweets from tanya77 actually has nothing to do with the Yahoo demographic information, which itself is rather suspect. The photo's just there to attract attention.
I have a Yahoo account. I could have claimed to be 13 (no younger, because of COPPA) or 93 when I set it up, and Yahoo has no particular way of verifying that. The location information I have on my account is similarly unverifiable. (That, I can say for sure, because it's incorrect.) Moreover, you can't even trust the IP ranges: my default method of connecting to the internet is via the cell network, so my IP addresses can be and generally are all over the Northeastern US. When I'm not logged in they have should have no access to the demographic information in my account, so a large number of searches ought to have no useful information at all.
The Yahoo story referenced by Good itself uses the number 100,00% twice--one commenter notices this and asks "What is 100,00% in ordinary numbers?"--a bad mistake on a post about statistics.
While the Yahoo story highlights the "Younger Generation", and talks about how "[e]very single state in the nation showed heightened search volume", we don't actually know how many of the people searching are from within the United States. We assume they're typing searches in English, but that's also not actually stated in the article. I think there's more of a chance that someone outside the United States might have missed learning about what was an attack on the USA, but there's also no way to tell this from the article. (The unspoken implication that only American web searches are being discussed is particularly noteworthy given that the subject in question was a Saudi and the assassination took place in Pakistan. But it's unsurprising in American news stories.)
My suspicion about the tweets is that many of them are coming from ironic hipsters reacting to jingoism on their friends lists, but that's just my guess. In any case there's no way to match them up with people searching on Yahoo.
But the original point I made in my earlier post still stands: if you are using Yahoo search as your primary search tool, you may also be making some other mistakes.