I probably should have been a little more explicit, but Cisco's IOS stands for Internetwork (or Internetworking) Operating System although you'll sometimes see it shortened to Internet Operating System. I'm not sure what Cisco has tried to trademark in terms of that phrase, but regardless you'd run into conflict with the acronym (IOS), which is widely attributed to Cisco. My point wasn't necessarily to argue the merits of your use of the term, only that it will lead to confusion (other people have posted similar comments to your blog).
We may be arguing semantics, but Cisco IOS definitely fits the traditional definition of an operating system more so than what you've described. While I agree with what you say in regard to how Internet-based applications will rule the desktop, I don't see them replacing the desktop operating system anytime soon.