I’ve noticed that active tweeting has resulted in fewer potential blog topics. Why? In Twitter, I can comment on something very quickly. Composing a blog post takes much more energy.
For example, I love Python Essential Reference, and I pre-ordered the fourth edition. (David Beazley is The Man!) I recommended PER on Twitter (and even had a Twitter conversation about it, which I cannot find now because Twitter search sucks like a Hoover), and therefore didn’t feel an impetus to write a post about it. I had quickly and easily satisfied my urge to recommend the book, via Twitter.
Others have also noticed this effect. Other posts are more wordy deep than necessary on this… I don’t see the comparison as cosmically subtle. Tweets have a lower creation cost than blog posts. Duh! One hundred forty characters and -boom- you’re done. A blog post can be pithy — indeed, that’s some bloggers’ preferred writing style — but my kind of posts demand some thought, editing, maybe image or quote insertions, adding links, etc. The work for even a simple post is at least 100x that of a Tweet.
Interesting.
Seek Nuance 
Why don’t you post 140 characters max blog posts then? Isn’t there a wordpress plugin for that?
Twitter’s format, mechanics, and community standards allow for less formality than a blog. At least, it feels that way to me.