It's a stretch for most people to run a server in Amazon's cloud, but if you're an experienced computer user, you should be able to do it, especially with some trial and error and patience. Once you have it running, it can be very rewarding.
On the other hand, River2 is the one server-based app that you can actually run on a computer in your den or family room.
You can operate rivers for others. Every user gets a river. To create a new user, choose OPML Server from the dropdown menu at the right edge of the screen, and then click on New User from the menu. Enter a username and password.