A sequence is a collection of events. Each event has a title, a time, and content. Sequences are displayed in a timeline and as a list.
You may view the public sequences made by others, or you may create your own and share them.
Feeds are collections of a website's links ordered by time. You can view feeds in a variety of tools, such as Google Reader. Viewing them here allows you to see a timeline of the current content in the site's feed.