Good from EFF to advertise companies who have a good behavior, but what sensitive information does reddit manage? It seems to me like it's only logins and IP ad

Good from EFF to advertise companies who have a good behavior, but what sensitive information does reddit manage? It seems to me like it's only logins and IP addresses, so it's not like they are in charge of emails, maps of where you've been/where you go and personal calendar, is it?