Business Coming to "80s" Office Building on Polk in Printers Row?

A reader writes:

Hey- 

Have you noticed that construction has started inside the rather 80s looking office space on Polk that is across the alley from Blackies? (sorry, don't know the address!). It has been vacant for the 3 years I have lived in Printers Row. 

Just wondering.... 

While we aren't sure if this is the building, we're guessing it is what the reader is talk about:

We don't know what is going on, does anyone have a clue if a business is moving in or if they're just modernizing to try to attract a leasee?

UPDATE (Hat tip AD!)
LOUISVILLE, Colo.– January 18, 2012 – zColo, a Zayo Group company, announces it is opening a facility in downtown Chicago, located at 600 South Federal St to deliver colocation and interconnection services. This will be zColo’s first location in downtown Chicago and 13th facility in the U.S. The carrier neutral colocation space will offer 8,500 sellable square feet and support up to 200 watts per square foot for high-power density applications. Services are anticipated to be available by the end of Q2 2012.

The site will leverage Zayo’s Bandwidth Infrastructure including its metro fiber network in Chicago and access to its 44,000-mile national network. The facility will offer a new downtown connectivity option to serve financial industry, media and other internet content customers.

 “Industry reports show that growth in demand for data center services in Chicago has exceeded supply by 50% over the prior two years,” states Chris Morley, President of zColo. “As a carrier-neutral provider, we plan to partner with other carriers in the Chicago area to support this demand.”

(Hat tip:  SL!)