This essay, advocating an affordance perspective on digital dialogic communication, contributes to the public relations scholarship in three ways. First, to answer the recent call to re-imagine dialogic principles on social media (Sommerfeldt & Yang, 2018), we propose “Mediated Dialogic Model” which expands the “ease of interface” dialogic principle to “sufficient affordances” and positions it as the technical foundation and requisite of digital dialogues. We empirically validate the model by taking advantage of Twitter’s recent affordance change which increased its character limit from 140 to 280 on November 7, 2017. Second, utilizing the dataset, we examine the relationship between dialogic principles and engagement indicators on Twitter, and replicate findings from previous studies on Facebook (Men, Tsai, Chen, & Ji, 2018) that useful information improves engagement outcomes while return visit generation has a negative effect. Third, and most importantly, we recommend using affordance theory to rephrase heated discussions on the tension between digital media and dialogic communication, to improve the relevance of dialogic theory for the digital age, and to re-examine relevant concepts in digital public relations.