The document summarizes findings from the OurSpace project, an e-participation platform used by young people across four European countries. Over its three-year period, the platform had over 4,300 users who engaged in 45 complete policy debates through posting, discussing, voting, and summarizing topics. The most successful engagement strategies included offline events, direct communication campaigns, and dedicated topic campaigns. Key lessons learned were that language barriers hindered cross-national debates, qualitative participation in deliberations takes a long time compared to social networks, and moderation is needed to guide discussion.