Background Digital peer support is an increasingly used form of mental health support for young people. However, there is a need for more research on the impact of digital peer support and why it has an impact. Objective The aim of this research is to examine young people’s experiences of using a digital peer support tool: MeeToo. After the time of writing, MeeToo has changed their name to Tellmi. MeeToo is an anonymous, fully moderated peer support tool for young people aged 11-25 years. There were two research questions: (1) What impacts did using MeeToo have on young people? (2) Why did using MeeToo have these impacts on young people? Methods A mixed methods study was conducted. It involved secondary analysis of routinely collected feedback questionnaires, which were completed at two time points (T1 and T2) 2-3 months apart. Questionnaires asked about young people’s (N=876) experience of using MeeToo, mental health empowerment, and well-being. Primary data were collected from semistructured interviews with 10 young people. Results Overall, 398 (45.4%) of 876 young people completed the T1 questionnaire, 559 (63.8%) completed the T2 questionnaire, and 81 (9.2%) completed both. Descriptive statistics from the cross-sectional analysis of the questionnaires identified a range of positive impacts of using MeeToo, which included making it easier to talk about difficult things, being part of a supportive community, providing new ways to help oneself, feeling better, and feeling less alone. Subgroup analysis (paired-sample t test) of 58 young females who had completed both T1 and T2 questionnaires showed a small but statistically significant increase in levels of patient activation, one of the subscales of the mental health empowerment scale: time 1 mean=1.83 (95% CI 1.72-1.95), time 2 mean=2.00 (95% CI 1.89-2.11), t59=2.15, and P=.04. Anonymity and the MeeToo sense of community were identified from interviews as possible reasons for why using MeeToo had these impacts. Anonymity helped to create a safe space in which users could express their feelings, thoughts, and experiences freely without the fear of being judged by others. The MeeToo sense of community was described as a valuable form of social connectedness, which in turn had a positive impact on young people’s mental health and made them feel less isolated and alone. Conclusions The findings of this research showed a range of positive impacts and possible processes for young people using MeeToo. Future research is needed to examine how these impacts and processes can be sustained.

BACKGROUND Evidence suggests that digital peer support tools could improve mental health, social functioning, and quality of life amongst young people, particularly during the COVID-19 pandemic. However, there is a need for more research on the impact of digital peer support, young people’s experiences of digital peer support, how it can be improved, and the barriers and facilitators to engaging with digital peer support. OBJECTIVE The aims of this evaluative study of MeeToo were to investigate: (1) what young people thought of MeeToo, (2) how and when young people used MeeToo, (3) young people’s experiences of using MeeToo, (4) the impact of MeeToo on young people’s connection to others, wellbeing, and their ability to support others. METHODS A mixed methods evaluation design was used consisting of a qualitative and quantitative methodology. Semi-structured interviews with n = 10 young users were analysed using thematic analysis. Routinely collected activity data and experience and outcome questionnaire data were analysed from a n = 398 in the cross-sectional sample and n = 559 in the longitudinal sample. RESULTS Two main themes were identified in the qualitative and quantitative analyses: “I don't like talking to people I know, but having an anonymous platform…is a really good thing”, and the MeeToo sense of community. There was also change over time in the longitudinal sample suggesting that young people using MeeToo increasingly learned new ways to help themselves and seek support. CONCLUSIONS Overall young people support the concept of MeeToo and have had a positive experience of the app. Young people welcome MeeToo as a safe space for both personal reflection, peer support and gaining insight in their mental health and wellbeing.