There are currently multiple format of feeds: RSS 2.0 (and their old formats), Atom, JSON feed, Microformat h-feed.

The author describes the content-type for each, the absolute URLs norm in the feed and how to advertise them on web pages. Some good practices such as self link, cachine with Cache-Control, styling, feed titles and dates, conditional requests for the feed based on ETag or Last-Modified. WebSub seems to be an interesting standard. Bot access, categories, changing URLs, CORS and performance are also addressed.