There's that saying "there's nothing new under the sun". That's true generally. And it's particularly true on the internet. There are just so many blogs about internet marketing, for instance. They all have the same or very very similar information: how to get traffic, how to build backlinks for free, etc.
So it seems that to distinguish yourself from the pack you have to do one of two things (or both of them together): Be the very first to post the new information. Or you have to write uniquely insightful posts about your niche.
That's not an easy thing to do. And it's very hard to do consistently.