How are Web feeds useful?

Related questions

1. What is an RSS subscription?
2. What is Feedly used for?
3. What is the benefit of RSS feed?
4. What is my RSS feed URL?
5. What is XML feed?
6. How does RSS subscription work?
7. What can you do with an RSS feed?
8. How do I add an RSS feed?
9. Why are feed readers useful?
10. What is a web based reader?

Tags

1. #updates
2. #notify
3. #content
4. #provide
5. #users
6. #providing
7. #itself
8. #include
9. #world
10. #frequently
11. #format
12. #feeds
13. #websites
14. #often
15. #rather
16. #updated
17. #summaries