I'm using Office 365 Enterprise E3

Question

I just a SP user, not on an admin level and I am not a very technical person. I know I'm using SP O365 Enterprise E3 but I'm not sure what that means. I'd like to know the difference between SP Online and SP Server. I see that many terms are used and some may be the same and I just want to be clear. Thanks!

Answer 1

SharePoint Server (aka "on-premises")
SharePoint Server is the SharePoint software deployed and administrated by your own IT staff. It means the software has been bought from Microsoft and installed on servers (machines) your enterprise owns. It's then the responsability of your enterprise to run it (maintain, update, secure, etc.).

SharePoint Online
On the other hand, Microsoft also sells SharePoint as a subsription, called Office 365. So Office 365 is the subscription your enterprise bought from Microsoft. Office 365 contains access to emails, SharePoint and more. In this case, SharePoint is called "SharePoint Online".
Microsoft does host SharePoint, and offers access to it for his customers. This is sold on a per-month and per-user basis (somewhere between $5 and $15 /month/user).
Office 365 comes with different options. Options are grouped in "packages" (called plans), and your package is called "E3", meaning it comes with such and such services, options, disk storage, etc.
Plans descriptions can be found here if you're interested.

Note: Office 365 is part of the big "Cloud" master plan every software vendor now pushes for. Also, there's different flavors of "Cloud", and that one is "SaaS" (Software as a Service), meaning Microsoft sells a subscription for a real piece of software, not something to help you build a software (like IaaS or PaaS do).

Technical/conceptual differences
SharePoint Server and SharePoint Online are very similar (SP Online used to be an actual SP Server deployed by Microsoft on Microsoft-own servers). But these days, the 2 products really diverge, meaning they're less and less comparable, but core features are still the exact same. What changes is the UI, the new features (brought to SP Online, and later, maybe to SP Server), and the fact that SP Server can be much more customized!