You just shared a most awesome resource with your followers on Twitter. It’s not your own resource but rather one you found on someone else’s blog. Regardless of the author, you know your followers will find it useful.
Earlier you were busy sending an email message to a colleague in response to their newsletter. The personal story they included was touching and inspired you to write back. But you didn’t tweet that article. Why not?
Building relationships and getting shared are only two of several possible reasons for creating content via newsletter and blog. Which is best? That depends on your own goals… and why it’s so important to have well-defined goals.
Likely you will use a combination of both types of content but in different situations. For example, I tend to include experiential stories in my own newsletter. But on my blog I include more of the type of information that’s great for sharing.