PURPOSE: To explore caregivers' writings about their experiences caring for adult individuals with cancer on a social media health communication website. PARTICIPANTS & SETTING: Journal entries (N = 392) were analyzed for 37 adult caregivers who were posting on behalf of 20 individuals with cancer. CaringBridge is a website used by patients and informal caregivers to communicate about acute and chronic disease. METHODOLOGIC APPROACH: A retrospective descriptive study using qualitative content analysis of caregivers' journal entries from 2009 to 2015. FINDINGS: Major categories identified in caregivers' online journals included patient health information, cancer awareness/advocacy, social support, caregiver burden, daily living, emotions (positive and negative), and spirituality. IMPLICATIONS FOR NURSING: Nurses often recommend using social media as a communication strategy for patients with cancer and their caregivers. The findings from this study provide potential guidance nurses may wish to offer caregivers. For example, nurses may talk with caregivers about how and what to post regarding treatment decisions. In addition, nurses can provide support for caregivers struggling with when and how often to communicate on social media.