Jim's comment, "an rss feed that would automatically check your favorite sites and bring you their content when they were updated," explained quite well the reason I use an aggregator site like Bloglines (now defunct) and Google Reader, both free of cost and mostly free of advertising.

I like the convenience of having, on a single platform, most of my favorite sites listed in the left hand pane if those sites have feeds added since my last visit. If I click on the site on the left hand side, the right side pane shows the title of the feed and a brief description or the entire article.

I can mark the article as a favorite, allowing me to keep it archived, I can select it as "unread", which will keep it in queue for the next time I visit, or I can read it and move along and it will not display during the next visit, since it has been read and not marked.

Very convenient. I have links to newspapers and magazines, blogs, fun sites like icanhascheezburger, science news, just about anything you can name, all in one place. For free. I have about 40 sites in my account.

Very useful for places that don't have new material very often, because I don't have to keep checking. The aggregator will display that site only when there is a new item.

And very useful for sites with lots of new things (like Boing Boing), because I can skim through all of the new stuff quickly and selectively read or save only what is interesting to me.

It's the lazy woman's trawler.