Jason Calacanis, an Internet entrepreneur, says he is retiring from blogging. Simultaneously, he has launched a limited subscriber newsletter. You might want to join it, if it’s not too late. Click here.

In his email to that list yesterday, Calacanis explained why he is retiring from blogging.

One hundred of you responded with amazing suggestions to my email last night. After that I realized that blogging is not longer the medium for me–email is. 100 amazing suggestions in 12 hours from a pool of around 500 email subscribers. That’s 20% response rate with really considered words and no drama.

This is really interesting (and it’s not April 1, so I assume this isn’t some kind of hoax or prank, though you never know). Calacanis was co-founder of Weblogsinc.com, one of the first big commercial blog networks. It was sold to AOL in October 2005 for a reported $25 million or so. So Calacanis is someone who really knows blogging and has been doing it for a long time.

You can still a lot of his online movements, of course. In addition to the email newsletter, there’s his Twitter stream, his photos on Flickr, and more in the right sidebar of his blog.

Update: Scoble says Calacanis is playing us. Could be right.