Have you download Mozilla Firefox 4? If you have install and use it, there are some miss. RSS Icon on the Address Bar has been disappear on Mozilla Firefox. This not god, exspecially for me. I am big fans of Mozilla Firefox. I use Mozilla Firefox from the beginning and until today I still love it.
I don’t know what the plan and why Mozilla has decided to remove the RSS icon from the address bar and move it to the bookmark menu. Maybe the most reason is probably the lack of awareness about this feature and the functionality. Like we all know Mozilla Firefox 4 also move status bar and merger it on Address Bar, we got this info from @vikingkarvur and @valentmustamin.
If you really want to bring RSS icon back into Address Bar in Firefox 4. You need install this extension and your RSS Icon will back. This is what RSS Icon Developer has said
Specifically, when a page contains link tags in it’s header with a type of application/atom+xml or application/rss+xml it places the orange RSS icon into the right side of the location bar (a.k.a. urlbar, awesomebar).
If one and only one feed is detected, then clicking on the icon invokes your feed-handler (see about:config browser.feeds.handler). If multiple feeds are detected, it popups up a little menu to allow you to select which feed to add.