Daka is a shoe company mentioned in iPromote Techfoots. They manufacture the faulty Techfoots shoes and pay Carly, Sam, and Freddie to endorse them.
This brand is also mentioned in two other shows made by iCarly creator Dan Schneider, one being Drake & Josh in the episode "Really Big Shrimp" and the other being All That. It is possibly a parody of Nike brand shoes.
The building shown in the image is the Seattle Central Public Library.