Can I use SharePoint online like I would SharePoint enterprise? Say I wanted to create multiple similar and related external facing sites; do I have a limitation on how many external sites? So I can take advantage of all features of SharePoint like mail, reporting and storage without deploying SharePoint on premise or creating s custom portal site. My plan is to run everything on the cloud. What would be the best approach?
You can take advantage of all of those features in the cloud without needing on-prem SharePoint. When you say “external facing sites,” do you mean anonymous public facing sites or do you mean authenticated extranet sites? I think you only get 1 anonymous public facing site.