I've wondered if any attacks on the US would serve to trigger an all-out war on Muslim nations and that is what they are after. An excuse to gather support for all of them to ally themselves against the rest of us. Any big attack like this article is talking about would certainly produce a big response from us. At least, I hope it would.
I have thought that myself -- in Transactional Analysis, I think they call what Osama is doing, "Let's You and Him Fight." Only this version is being carried out in the nth degree, rather than at the interpersonal level.
There is another synthesis of Osama's intentions being built at Jamestown.org, a good antiterrorist site -- the "bleed them white" thesis, under which Osama recognizes that good economic health is incompatible with fighting a war. His objective is to defeat the U.S. by provoking us into overexertion. He economically carries out spectacular attacks, provoking broad responses costing us many, many times what his attacks did, and he does it over and over until we can't do it any more, and presto, he wins.
That's their idea, anyway. A variation on "rope-a-dope", Osama's warfighting plan assumes several things about our conduct and capacities. We can win by changing the assumptions and rules.