Taking the logic of online connective action from an information-processing viewpoint, an online experiment (N = 208) was done to examine whether individuals’ cognitive elaboration on messages received from different sources (personal: friends, family, vs. impersonal: organization) mediates their willingness to engage in connective-type collective activities on social media (e.g., commenting, "Liking"); and whether this indirect influence is biased by perceived source credibility. Results revealed significant influence from personal sources. Cognitive elaboration positively mediates this influence and was conditionally affected by high source credibility. Direct influence from personal issue involvement and perceived self and technological efficacy was also observed. Theoretical contributions (i.e., cognitive demands at individual level) and practical implications (i.e., enhancing organizational credibility, popularity of easy-to-do acts) are discussed.