Your content is broken into different capsules:
Text - just to write text
Links - list some links
RSS feeds - re-syndicate feed content
Service listings - eg. ebay, amazon
A hub can be made up of all this type of content, you also describe your hub with tags, and what do you know, you can discover other hubs with the same tags…each hub also has a generated list of related hubs.
Others can leave comments at your hub, as long as you have enabled the comments capsule…you can also bookmark, and email a hub, where’s the RSS feed.
Check out the eConsultant hubs, most of these just use the text capsule.
Some example hubs…