Online art marketplace BoomBoom Prints has been sold to an undisclosed buyer. Former CEO Brett Brohl declined to name the buyer or deal terms, but said BoomBoom remains headquartered in the Twin Cities. The company's founders, including Target Corp. business accelerator leader Ryan Broshar, decided to sell after determining the startup was more likely to succeed as a lifestyle business than a venture-backed growth company, Brohl said in an interview. "We didn't ramp revenue fast enough so...