When I was reading on reader, I found it quite not up to date. There might be two reasons. One is that reader did not get the latest feed, while the other is the feed itself is not updated.
As information explodes, a huge number of bytes were generated day by day, hour by hour. With newspaper, we know what happened yesterday; with TV, we know what happened today; with Internet, we could know what happened just now. However, these are all limited to public concerned events. They are not what we are most interested in.
When search engine came up, we were able to find what we want by typing some keywords. When searching, we got what was being. The information we searched on was crawled by robots days or even months ago.
One approach to solve time critical problem is subscription and notification. In this way, every subscriber is notified whenever an event happened. It is better than "publishing and waiting till someone sees it" method. But still, there are problems. One is that the subscription and notification server would become a bottleneck. Another is that we could not know what to subscribe before it happened. To solve the former one, a more powerful hardware or smarter software on cooperated computers might do. To the latter, only can we believe there is a wizard.
So, here comes the necessity of existence of real time search.