good points. You may be interested in a “personal” shortener then. They provide a short URL path, but start at your own domain. So instead of “thingly.me/b17fe8″ your get “yourdoman.com/b17fe8″. Of course, if your domain is longish by itself, the shortening will be less effective.

“I can think of only one logical reason to use an URL shortener in the own blog: To cloak a link the target of which you don’t want to be immediately visible to the reader (an affiliate link, for example).”

I would tend to agree with this only as a partial demographic. Outside of limited 140 char sets for a Twitter entry, I personally shorten for one of two purposes:
1) in order to allow the end user to easily transcribe from mobile device to workstation browsers
2) in order to avoid a line break in a link sent via email, where the end user is too confused to understand the issue of the ‘broken link’

I also think that a URL shortening service is a way to hide the originating URL server, but for me, I do not use them to hide.