RSS is a way of keeping tabs on new content from a website (mostly blogs) without visiting the actual site in question. A feed is generally indicated by this icon 
. To manage your RSS feeds you will need a so called RSS reader, these come in webbased or installable program variate (I personally use Google Reader). The wonderful thing is that after you have subscribed to a feed you can view it via the RSS reader and never miss an update without the hassle of having to visit site itself.
Some of my RSS feeds (most of which turn up in the LifeStream):
gray-um.com main RSS or subscribe via 
e-mail
Some of the RSS feeds I follow:
CHUD (reviews about movies)
Coding Horror (Jeff Atwood’s tech related blog)
daily dose of imagery (Sam Javanrouh’s photoblog)
Explosm (Cyanide & Happiness webcomic)
Felicia Day (blog)
/Film (movie blog)
Garfield (webcomic)
Lifehacker (GTD blog)
nixcraft (*unix related blog)
Schneier on Security (Bruce Schneier’s take on Security)
Smarterware (Gina Trapani about smarter software)
XKCD (Randall Munroe’s webcomic)
Ylliks (René Slaats’s blog)
