  Understanding susceptibility to online influence is crucial for mitigating
the spread of misinformation and protecting vulnerable audiences. This paper
investigates susceptibility to influence within social networks, focusing on
the differential effects of influence-driven versus spontaneous behaviors on
user content adoption. Our analysis reveals that influence-driven adoption
exhibits high homophily, indicating that individuals prone to influence often
connect with similarly susceptible peers, thereby reinforcing peer influence
dynamics. Conversely, spontaneous adoption shows significant but lower
homophily. Additionally, we extend the Generalized Friendship Paradox to
influence-driven behaviors, demonstrating that users' friends are generally
more susceptible to influence than the users themselves, de facto establishing
the notion of Susceptibility Paradox in online social influence. This pattern
does not hold for spontaneous behaviors, where friends exhibit fewer
spontaneous adoptions. We find that susceptibility to influence can be
accurately predicted using friends' susceptibility alone, while predicting
spontaneous adoption requires additional features, such as user metadata. These
findings highlight the complex interplay between user engagement and
preferences in spontaneous content adoption. Our results provide new insights
into social influence mechanisms and offer implications for designing more
effective moderation strategies to protect vulnerable audiences.
