This is likely because Google had such a large userbase that they were able to update more people's feeds at the same time than a lot of other places like newsblur and feedly can right now.
I also imagine it's because google was requesting the feeds more often than others, or leveraging the feedburner system to know when they were updated and other such things.
I also imagine it's because google was requesting the feeds more often than others, or leveraging the feedburner system to know when they were updated and other such things.