An RSS feed reader relieves you of having to keep track mentally of what you have and have not read, and it saves you time because you don't have to continually revisit multiple sites.
I use an RSS reader to get updates whenever my favourite Etsy sellers list new fiber and tools. I also use it for blogs, a knitting podcast, and some online forum discussions about handspinning that I want to follow.
You should know that in exchange for this convenience, I give away some of my privacy, since the feed reader knows what I read and when I read it. The one I use analyses the content of my RSS feed subscriptions and then makes recommendations for new feeds, overt evidence of data mining which I find a little disconcerting.
I'll leave you with a quote from Stephen Baker in the October 21, 2008 CBC online article, "Mining for Data"
Society is moving in such a way that it [privacy] is going to become increasingly inconvenient. Like, try to find a pay phone in Vancouver. There are not too many anymore. Or if you want to throw quarters into the [electronic toll booth] every year there is one less tollbooth for you. So you've got all the losers lining up to throw their quarters in the machine and all the people that are free and easy with their data just zipping past.
I think we talk a lot about privacy and people complain about it and fret about it, but at least in this country and I'm not sure about Canada, when given a choice between privacy and monetary savings, they go for the savings every time. And given a choice between privacy and convenience, they go for convenience. And given a choice between privacy and the promise of security, they go for the promise of security.