The goal of this clinical trial is to learn if using an intervention website (Mosaic) improves selected patient-reported outcomes in adult blood cancer patients undergoing allogeneic or autologous stem cell transplant, compared to using an educational website (control group). Patients will be recruited prior to their scheduled transplant, then randomized to use one of these two study websites throughout the study. They will complete five assessments during the study: one before transplant (baseline) and four after transplant (2, 4, 6, and 8 month follow-ups). The main questions this trial aims to answer are: 1. Compared to patients using the control group website, do patients using the intervention website report greater improvements in general psychological distress, cancer treatment-related distress, physical symptoms, and health-related quality of life? 2. Are these benefits at least partially explained by improvements in perceived preparedness, self-efficacy, and approach coping and/or reductions in avoidant coping and perceived stress? 3. Do some patients benefit more from using the intervention website than others? Specifically, we will examine whether patients' primary language (English/Spanish) and their initial psychological distress are related to the benefit they get from using the intervention website. We will also explore effects of sex, race, ethnicity, and transplant type.