Difference btwn wp-rss2.php and URL feed

/feed/ is a “cruft-free” URL (also called a “pretty URL”). To use cruft-free URLs, you need to use mod_rewrite and .htaccess to control your permalink structure.
Using Permalinks should help explain things a bit more. Keep asking if you still have questions!

Hello,

I asked the very same question a few months ago. After getting some great answers at this forum, my conclusion is that the simplest for me (beginner-level user) is to use this

http://yourdomain.com/wp-rss2.php

It works (test mine, if you like, at the sidebar at this page: http://www.youthtopia.com )

If you want to use this, then just check your feeds on your home page (most likely in sidebar.php — but you might have another one in your footer) and then change the

http://yourdomain.com/feed

to

http://yourdomain.com/wp-rss2.php

Best wishes … RB