As if 2020 weren't an eventful enough year in the mobile world, market research firm Newzoo is predicting 2021 to continue re-shaping the space. The firm today detailed five trends to keep an eye on in the mobile market this year, starting with Apple's imminent requirement that apps receive opt-in permission from users in order to track their activity for personalized advertising, part of the ID For Advertisers (IDFA) system. "While it is too early to determine the changes' exact impact, we expect to see a short-term lower spend on user acquisition across iOS in 2021," Newzoo said. "Instead, this spend may flow into Android, web, or other channels while the industry attempts to regain its footing.