You have probably stored hundreds of bookmarks in your web browser to store a list of websites and blogs that you liked and planned to visit regularly. That soon gets out of hand because it is really hard to browse through your bookmarks often and visit and read new posts in those sites. Is there a way you could tell if there was anything new posted in any of those sites so you could visit only those? Yes. You could subscribe to daily updates by email. You can also subscribe to the RSS feeds from you web browser. These would typically create a tab on your browser and opening those would show you new content for the corresponding site. But even this gets unmanageable at times.
I decided to give Google Reader a try recently. So far, it has helped be add my favorite sites to the list and keep them all in one place. It has the appearance of an email reader, with each category or site listed on the left, also showing the number of unread or new posts in parantheses. So in a quick glance, I can see the list of all my favorite blogs and news sites, and also get a feel of how many new posts are there in each. If I feel like reading any of them, I just click on them and they show up in the middle of the browser, very much like an email message.
In short, this is like an advanced bookmarking tool that is associated with your Google account, so you can access it from anywhere and from any computer.