You are likely correct that it's unlikely any of these companies' futures will change appreciably because of this coverage. However, PR can definitely make a real difference in a business--see Aaron Patzer's thoughts on this (no particular source, but he talks about it a lot). To take your airline example, Virgin America invested a ton in PR when they launched.

Also, I think writing off successful PR (even in this particular article) as being a company with or without a human interest angle is wrong. I don't think there's anything particularly human interest-y about Posterous, or syncing cell phone data to computers. Certainly the fundamentals of the businesses are not the high order bit either, but that doesn't seem any more like any inherently good decision basis than many other things.