Here is an outline of what I'm looking for and a proposed solution. I'm curious to get comments before I dive in to build it.
- I don't want to blog fully publicly.
- I don't want to blog on Facebook. Facebook is broken. 
- Apparently, the verb "to blog" has finally crept into my vocabulary to replace "keep a weblog". Eek! Sorry.
- If my blogging solution requires my friends to create a new account and log in to view my posts, they won't read my blog. (This covers both LiveJournal and a private password-protected site.)
- There may be such a thing as authenticated RSS, but if one person gives the password for my blog to Google Reader, then its security is effectively null and void. (Right?)
Proposed solution: distribute posts consisting of a teaser + read more link using a private Twitter stream. The link in each teaser goes to a (Drupal-based) website which shows content only to authenticated users--but people authenticate using their Twitter credentials.
So now people can find out about my posts using whatever Twitter client they like (and many friends already use one), and they don't have to create a new login to actually read them. They may even not have to give Twitter their password again if they're already logged in, just allow Twitter to authenticate them to my site with a click on a button.
Seems like a nice arrangement.
Tech details: Twitter exposes an OAuth authentication API, and there is existing OAuth support for Drupal which hides Drupal's user registration/login altogether. People are sent to Twitter's site to log in--my site doesn't find out their Twitter password. Under the covers, Drupal will create a local user account linked to the remote credentials. Presumably my site will learn the visitor's Twitter username, so I can know who's who & let them post comments. If Twitter's authentication is some day completely compromised, I can turn off the OAuth integration, and my blog posts will still be private.
Am I missing anything? Comments?