I think the biggest outrage you'll hear will actually be from consumers who have to pay an additional 9% for Netflix, iTunes, Spotify, Pandora, etc.
The biggest impact may well be tech start ups, which will see a significant source of their expenses increase overnight by nearly ten percent. Pretty much any tech oriented business is either using or providing cloud services, so this tax could have a very real, very negative impact very quickly. How can a cloud provider in Chicago compete if they are forced to add that 9% tax to their services? That's going to present a problem. Companies such as law firms that have large bills for cloud services such as Lexis-Nexis are going to have to spend significantly more money each month for those same services, instead of spending it on increased compensation, which ironically would be taxed at a higher rate anyway.
This also sends a message to potential start-ups that Chicago is not a friendly city for their business, and I suspect many will look elsewhere.
On the other hand, Chicago claims they will see millions of dollars in increased revenue. They estimate $12 million annually, which seems pretty low when you add in all of the companies that use cloud services, so I'm wondering if they are only counting the consumer/entertainment portion of the tax. I'm also doubtful they are accounting for the loss of revenue from decreased salaries and loss of potential new business because of this tax.