RSS submission is where you take your Web site's RSS feed and submit it to syndication services. I'm not at home right now so I can't tell you which ones to use off-hand, but the basic rule of thumb is to only use high-quality reputable syndication networks rather than spammy low-quality ghettos that'll just spam your feed all over the place sucking down more of your bandwidth than a fat man (and before anyone gets offended by this, I'm pretty darn "porky" myself though I don't binge on everything - I just don't have much of a social life since taking up freelancing last year) at an all you can eat buffet.
Or you can use an automated program to do the work for you, such as RSS Submit http://www.dummysoftware.com/rsssubmit.html