i've hired in mobile app marketing across several US companies. honestly, recommendation letters aren't the norm for internships in this space. i've seen maybe one or two applicants include them. It's more about portfolio, app store conversion examples, or a short case study. Some older-school agencies or corporate roles might ask for them - especially if HR is stringent. But in my experience, a solid network and direct referral beat a formal rec letter any day. that said, always have one ready if asked. Being prepared never hurts